Question

Variable y varies directly with x2, and y = 18 when x = 6. Which graph represents the quadratic variation?

Answer 1

lets find the equation that represents that relationship:
y = zx^2
plug in data:
18 = z(6)^2
18 = z(36)
z = 1/2
then the equation is:
y = (1/2)x^2
now you just have to plot that equation