Question

y varies directly as the square of x. When x = 2, y = 20. Find y when x = 4.

y = 40

y = 80

y = 100

y = 120

Answer 1

y varies directly as the square of x. When x = 2, y = 20. Find y when x = 4.

Y= Cx^2
20=C2^2
C=5
y=5x^2

y= 5(4^2)= 5*16 =80