Question 47773
a varible y varies directly with the square of x.  if x=2 when y=4, find the constant of proportionality, k.


Based on the 1st sentence y=kx^2
You need to find "k".
Based on the 2nd sentence 4=k(2^2)
k=4/4=1
Comment: I noticed you might have meant to type y=-4
If so, you would have -4=k(2^2). 
Then k would equal -1

Cheers,
Stan H.