Need help fast please.

The length of a rectangle is x times the square root of 100. the width is one-half y more than three-halves x. given that the area of the rectangle is 125 cm2, which equation could represent the rectangle in terms of x and y? a) 5xy − 15x = 125 b) 5xy + 15x = 125 c) 15x2 − 5xy = 125 d) 15x2 + 5xy = 125

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?

The diameter of the moon is about 3500 km. approximate the surface area of the moon using the formula for the surface area of a sphere, s = 4? r^2. write your answer in scientific notation.