Question

y varies directly as the square of x. When x = 3, y = 18. What is the value of y when x = 4?

Answer 1

to vary directly means to make the same move. you reflection in a mirror varies directly with you.

in other words, as x increases, y increases; as x gets small, y gets small

Answer 2

y = k*x^2; where k is called a constant of variation that makes both sides acutally equal

Answer 3

when x = 3 and y = 18 we get:

18 = k * 3^2

18 = k * 9

18/9 = k

k = 2 ; since we know "k" we can use this to find any relation between y and x now

Answer 4

y = 2 * x^2

when x=4 we get:

y = 2 * 4^2
= 2 * 16
= 32

Answer 5

thank you :)

Answer 6

youre welcome :)