# Matt says he can find the sum of 45+50 without rewriting it. Explain how you can solve this problem using mental math.

QUESTION POSTED AT 14/02/2020 - 04:41 PM

QUESTION POSTED AT 14/02/2020 - 04:41 PM

You could add 4+5 and then 5+0 and boom there's your answer!! Hope this helped

Ok what you have to do is get one variable in the two equations equal but opposite to each other. You already have that in y in the first one and -y in the second. Sometimes you would have to do some manipulation to get there.

Next, add the two together:

4x+y=-5

+ 2x-y=-1

---—--------

6x=-6

x-1

Now plug in the -1 for x in one of the formulas above:

4(-1)+y=-5 solve for y

-4+y=-5

y=-5+4

y=-1

Next, add the two together:

4x+y=-5

+ 2x-y=-1

---—--------

6x=-6

x-1

Now plug in the -1 for x in one of the formulas above:

4(-1)+y=-5 solve for y

-4+y=-5

y=-5+4

y=-1

ANSWERED AT 28/02/2020 - 08:03 AM

QUESTION POSTED AT 28/02/2020 - 08:03 AM

It's clear enough that the upper half of the cone falls below the upper sheet of the paraboloid, so that . Right away you can see that converting to cylindrical coordinates will be quite advantageous.

The intersection of the two surfaces occurs as a circle:

which is parallel to the x-y plane, has radius 8, and is centered at .

The volume of this space is given by the integral

where denotes the bounded space between the surfaces. Converting to cylindrical coordinates, this can be expressed as

which evaluates to .

ANSWERED AT 28/02/2020 - 07:57 AM

QUESTION POSTED AT 28/02/2020 - 07:57 AM

1*441 & 3*147 & 7*63 & 9*41 &21*21 are all factor pairs of 441

21&21 have the smallest sum and would make for the smallest perimeter

Answer:l=21 w=21

21&21 have the smallest sum and would make for the smallest perimeter

Answer:l=21 w=21

ANSWERED AT 28/02/2020 - 07:56 AM

QUESTION POSTED AT 28/02/2020 - 07:56 AM

P=2l+2w

100=2l+2w

divide both sides by 2

50=l+w

So what two numbers that have a sum of 50 have the largest product?

25*25=625 which makes for a large area, the largest

answer=l=25 w=25

100=2l+2w

divide both sides by 2

50=l+w

So what two numbers that have a sum of 50 have the largest product?

25*25=625 which makes for a large area, the largest

answer=l=25 w=25

ANSWERED AT 28/02/2020 - 07:56 AM

QUESTION POSTED AT 28/02/2020 - 07:56 AM

Recall that

You're given that , so omit the negative root. Then

Because , you have too, so omit the negative root again. Then .

Now,

You're given that , so omit the negative root. Then

Because , you have too, so omit the negative root again. Then .

Now,

ANSWERED AT 28/02/2020 - 07:54 AM

QUESTION POSTED AT 28/02/2020 - 07:54 AM

I believe H since those numbers are higher than all the others ones

ANSWERED AT 28/02/2020 - 07:50 AM

QUESTION POSTED AT 28/02/2020 - 07:50 AM

Their are 52 option for the first card, 51 for the second (because we already picked up on for the first card), and 50 for the third (because we already pickes up two cards)

52*51*50=132,600 possible hands

52*51*50=132,600 possible hands

ANSWERED AT 28/02/2020 - 07:47 AM

QUESTION POSTED AT 28/02/2020 - 07:47 AM

Answer choice E is the correct answer.

ANSWERED AT 28/02/2020 - 07:42 AM

QUESTION POSTED AT 28/02/2020 - 07:42 AM

f(x) = 1/(10-7) = 1/3, 7<x<10.

(a) P(at most 8.8 liters) = integral(7to8.8)f(x)dx = 1.8/3 = 0.6

(b) P(more than 7.4 liters but less than 9.5 liters) = integral(7.4 to9.5)f(x)dx = 2.1/3 = 0.7

(c) P(at least 8.5 liters) = integral(8.5 to10)f(x)dx = 1.5/3 = 0.5

(a) P(at most 8.8 liters) = integral(7to8.8)f(x)dx = 1.8/3 = 0.6

(b) P(more than 7.4 liters but less than 9.5 liters) = integral(7.4 to9.5)f(x)dx = 2.1/3 = 0.7

(c) P(at least 8.5 liters) = integral(8.5 to10)f(x)dx = 1.5/3 = 0.5

ANSWERED AT 28/02/2020 - 07:42 AM

QUESTION POSTED AT 28/02/2020 - 07:42 AM

Area of square = 4 square inches

Area of circle = PI * radius ^2

Area of circle = 3.14 * 1^2

Area of circle = 3.14 square inches

Area inside the square and outside the circle =

4 -3.14 = .86 square inches.

answer is .9 square inches

Area of circle = PI * radius ^2

Area of circle = 3.14 * 1^2

Area of circle = 3.14 square inches

Area inside the square and outside the circle =

4 -3.14 = .86 square inches.

answer is .9 square inches

ANSWERED AT 28/02/2020 - 07:37 AM

QUESTION POSTED AT 28/02/2020 - 07:37 AM

C cause the diamiter....

ANSWERED AT 28/02/2020 - 07:36 AM

QUESTION POSTED AT 28/02/2020 - 07:36 AM

Guessing on how the system is expressed:

The coefficient matrix has eigenvalues with corresponding eigenvectors . This means the characteristic solution is

The coefficient matrix has eigenvalues with corresponding eigenvectors . This means the characteristic solution is

ANSWERED AT 28/02/2020 - 07:36 AM

QUESTION POSTED AT 28/02/2020 - 07:36 AM

Can't be done without knowing what is...

But I can tell you that the average value of is given by

At the very least, we can compute the denominator, which is just the area of . You have

so the average value will be

But I can tell you that the average value of is given by

At the very least, we can compute the denominator, which is just the area of . You have

so the average value will be

ANSWERED AT 28/02/2020 - 07:36 AM

QUESTION POSTED AT 28/02/2020 - 07:36 AM

The arc length is then given by

ANSWERED AT 28/02/2020 - 07:36 AM

QUESTION POSTED AT 28/02/2020 - 07:36 AM

The volume is 60 cubic inches.

To solve, follow the formula**Volume = Length · Height · Width**. If you are solving without a calculator, simply multiply the length and the height first, then multiply the product of that by the width, 2 / 3.

V = 10 · 9 · 2/3

V = (10 · 9) 2/3

V = 90 · 2/3

V = 60 in.³

Hope this helps. Good luck! :)

To solve, follow the formula

V = 10 · 9 · 2/3

V = (10 · 9) 2/3

V = 90 · 2/3

V = 60 in.³

Hope this helps. Good luck! :)

ANSWERED AT 28/02/2020 - 07:31 AM

QUESTION POSTED AT 28/02/2020 - 07:31 AM

If r=13cm, the d is double that so it is 26cm.

ANSWERED AT 28/02/2020 - 07:27 AM

QUESTION POSTED AT 28/02/2020 - 07:27 AM

Raising to a negative power just makes the base value into a fraction

For example, x^-1 turns into (1/x^1)

This means that your equation goes from

7^-1+9^-1 to (1/7)+(1/9)

1/7+1/9 simplifies to 16/63 after all of the common denominator stuff

So, in short 7^-1+9^-1 = 16/63

For example, x^-1 turns into (1/x^1)

This means that your equation goes from

7^-1+9^-1 to (1/7)+(1/9)

1/7+1/9 simplifies to 16/63 after all of the common denominator stuff

So, in short 7^-1+9^-1 = 16/63

ANSWERED AT 28/02/2020 - 07:26 AM

QUESTION POSTED AT 28/02/2020 - 07:26 AM

B. The perimeter of the plot of flowers

The perimeter measures the distance around all the edges, which is how much rope he'd need

The perimeter measures the distance around all the edges, which is how much rope he'd need

ANSWERED AT 28/02/2020 - 07:25 AM

QUESTION POSTED AT 28/02/2020 - 07:25 AM

They appear to be the same option in this picture. I would report this question to your professor.

ANSWERED AT 28/02/2020 - 07:24 AM

QUESTION POSTED AT 28/02/2020 - 07:24 AM

You would typically be given two equations to solve for two unknowns with matrices.

ANSWERED AT 28/02/2020 - 07:24 AM

QUESTION POSTED AT 28/02/2020 - 07:24 AM

3x-8y=-35

- First thing you need move the 3x to the right hand like this one

-8y=-3x-35 ( positive move to another side change to negative )

And then you need to move -8 to the right hand to !

y=-3/-8 -35/-8 so you need to change the negative to positive y=3/8 + 35/8 ( 3/8 mean 3 over 8 )

The answer is y= 3/8 + 35/8

- First thing you need move the 3x to the right hand like this one

-8y=-3x-35 ( positive move to another side change to negative )

And then you need to move -8 to the right hand to !

y=-3/-8 -35/-8 so you need to change the negative to positive y=3/8 + 35/8 ( 3/8 mean 3 over 8 )

The answer is y= 3/8 + 35/8

ANSWERED AT 28/02/2020 - 07:24 AM

QUESTION POSTED AT 28/02/2020 - 07:24 AM

I think that it either c or that the sines cannot be used.

ANSWERED AT 28/02/2020 - 07:23 AM

QUESTION POSTED AT 28/02/2020 - 07:23 AM

So because there is a graph we can pretty easily find the solution, lucky us!

So the solution is where the two paths cross or intersect.

Going off of (x,y) so the x is 3 and the y is -5

so the solution is (3,-5)

So the solution is where the two paths cross or intersect.

Going off of (x,y) so the x is 3 and the y is -5

so the solution is (3,-5)

ANSWERED AT 28/02/2020 - 07:22 AM

QUESTION POSTED AT 28/02/2020 - 07:22 AM

Raise each side to the 3rd power (^3) making the equation 2x-5=125,

Then, add 5 to both sides, making the equation 2x=130

Lastly, we divide by 2, making x=65

If we substitute 65 for x, the equation is still true

3✓(2(65)-5)=5

3✓(130-5)=5

3✓(125)=5

5=5

so, X=65

Then, add 5 to both sides, making the equation 2x=130

Lastly, we divide by 2, making x=65

If we substitute 65 for x, the equation is still true

3✓(2(65)-5)=5

3✓(130-5)=5

3✓(125)=5

5=5

so, X=65

ANSWERED AT 28/02/2020 - 07:22 AM

QUESTION POSTED AT 28/02/2020 - 07:22 AM

The formula for the circumference of a circle is

C=2rπ

If r=4, then

C=2(4)π

C=8π

Since we know that 8*3=24, and that π is greater than 3, we can reason that 8π>24ft

or we could just use a calculator and solve for 8π

C=25.12ft

Answer:The circumference is greater than 24ft

C=2rπ

If r=4, then

C=2(4)π

C=8π

Since we know that 8*3=24, and that π is greater than 3, we can reason that 8π>24ft

or we could just use a calculator and solve for 8π

C=25.12ft

Answer:The circumference is greater than 24ft

ANSWERED AT 28/02/2020 - 07:19 AM

QUESTION POSTED AT 28/02/2020 - 07:19 AM

The center of data would be 2.8 because it is in the middle which means it is the median

ANSWERED AT 28/02/2020 - 07:15 AM

QUESTION POSTED AT 28/02/2020 - 07:15 AM

Area = pi * radius^2

A = 3.14 * 1.5^2

A = 7.07 square centimeters

A = 3.14 * 1.5^2

A = 7.07 square centimeters

ANSWERED AT 28/02/2020 - 07:14 AM

QUESTION POSTED AT 28/02/2020 - 07:14 AM

That is a fraction, if you want to put it into decimal form, it would be equivalent to 0.7

ANSWERED AT 28/02/2020 - 07:13 AM

QUESTION POSTED AT 28/02/2020 - 07:13 AM

I believe the answer is d

ANSWERED AT 28/02/2020 - 07:12 AM

QUESTION POSTED AT 28/02/2020 - 07:12 AM

You can find it by dividing 10 to 25 . The second way is to divided it to there common factors which in this case its 5.

ANSWERED AT 28/02/2020 - 07:12 AM

QUESTION POSTED AT 28/02/2020 - 07:12 AM