y varies directly with the square of x and when x = 5 , y = 100 . Find x when y = 196

Question

Write a function describing the relationship of the given variables.

Answer 1

y = k*x^2

 

100 = k * 5^2

 

100 = k*25

 

k = 4

 

 

y(x) = 4x^2

 

196 = 4*x^2

49 = x^2

 

x=7