You area told that y is proportional to x2 and that when y = 75, x = 5. a) Find a formula for y in terms of x. b) Find the value of y when x = 3. c) Find the value of x when y = 1200.

a) when y=75 x=5 and y is proportional to x^2, so the answer is y=___x^2
if x=5, then x^2 = 25, and 75/25=3, so the answer is y=3x^2

b) if x=3, x^2=9, if you multiply this by 3, you get the answer of 27.

c)if y=1200, 1200 divided by 3 is 400, and the square root of 400 is 20. So the answer is 20.