7) Vertex = V(2,3)
9) Vertex = V(2,1)
17) The smaller the absolute value of the coefficient of x², the larger is the opening of the parabola. (to compare, just take the absolute value of a)
Coefficients are (5), (-3) and (1):
Widest: f(x) =x², followed by f(x) = -3x² and the narrowest is f(x) =5x².
