Question

Marta is solving the equation s=2πrh+2πr^2 for h. which should be the result?

s/2πr-r=h

s-r/2πr=h

s-r/2π=h

s-2π/r=h

Answer 1

`(s)/(2\pi r)-r=h`

Explanation:

Given equation is
`s=2\pi rh+2\pi r^2`.

Now we need to solve this equation for "h" and match with the given choices to find the correct choice.

`s=2\pi rh+2\pi r^2`

`s-2\pi r^2=2\pi rh`

`2\pi rh=s-2\pi r^2`

`h=(s-2\pi r^2)/(2\pi r)`

`h=(s)/(2\pi r)-(2\pi r^2)/(2\pi r)`

`h=(s)/(2\pi r)-r`

`(s)/(2\pi r)-r=h`

Hence first choice
`(s)/(2\pi r)-r=h` is correct choice.

Answer 2

Answer: First option.

Explanation:

Marta needs to subtract
`2\pi r^2` from both sides of the equation:

`s=2\pi rh+2\pi r^2`

`s- 2\pi r^2=2\pi rh+2\pi r^2- 2\pi r^2`

`s- 2\pi r^2=2\pi rh`

Now she needs to divide both sides of the equation by
`2\pi r`, then:

`h=(s- 2\pi r^2)/(2\pi r)`

Rewriting:

`h=(s)/(2\pi r)-(2\pi r^2)/(2\pi r)`

Simplifying, she should get:

`h=(s)/(2\pi r)-r`

This matches with the first option.