The parabola y = ax^2 + bx + c is graphed below. Find a + b + c. (The grid lines are one unit apart.) The parabola passes through (-2,8), (0,0), and (2,8).
Since it passes through (0,0) then c = 0
So
a(-2)^2 + b(-2) = 8
a(2)^2 + b(2) = 8 add these
8a = 16
a = 2
And to find b
2 (2)^2 + b(2) = 8
8 + 2b = 8
2b = 0
b = 0
a + b + c =
2 + 0 + 0 =
2
+448 
