If x varies directly as y raised to the power of 2 and y=3 when x=18, find:

Question

i) the equation connecting x and y

ii) the value of x when y=5

iii) the value of y when x=98

Answer 1

x = ky^2

18 = k(3)^2 = 9k

k =18/9 = 2

i) x = k y^2

x = 2y^2

ii) x= 2(5)^2 = 2(25) = 50

x= 50

ii) 98 = 2y^2

y^2 = 98/2 = 49

y = sqr49 = 7

y= 7