The quantity y is partly constant and partly varies as the square of x.
a. Write down the relationship between X and Y.
b. When x =1,y=11 and when x=2,y=5. Find the value of y when x=4
y = mx^2 + b
now plug in your numbers
m+b = 11
4m+b = 5
subtract to get
3m = -6
m = -2
so b = 13
when x=4,
y = -2*4^2 + 13 = -19