The graph of a certain quadratic y = ax^2 + bx + c is a parabola with vertex (-4,0) which passes through the point (1,75) What is the value of a?
We have the form
y = a ( x -h)^2 + k where (h,k) = the vertex and (x,y) is a point on the parabola
So
175 = a ( 1 - - 4)^2 + 0
175 = a (5)^2
175 = 25a
175 / 25 = a = 7
