Thus, the standardized form of a quadratic equation is ax2 + bx + c = 0, where "a" does not ... We said that the graph of y = x2 was a function because it passed the vertical line test. .... Find the vertex of the parabola y = 2x2 - 12x + 7. ... To find the y-value, we would substitute 3 in for x, or find f(3) = 2(3) 2 — 12(3) + 7 = -11.