Question: how to solve quadratic equations by graphing and factoring?
Answer: Compare the equation with the standard form, y=ax2+bx+c . Since the value of a is positive, the parabola opens up.
So, y=0 implies, by the zero product property, x+4=0 or x−2=0 .
Substitute x=−1 in the equation y=−x2−2x+8 to find the y -coordinate of the vertex.