For what real values of c is 4x2+14x+c the square of a binomial?
The discriminant b2−4ac must be 0. So we have the equation 196−4c=0, and we need to solve for c.
Can you take it from here?
Here's another way:
(Incidentally, you should check your result for b^2 - 4ac BuilderBoi).
+2668 
