Q:

Help with Algebra! Completing the square!

Accepted Solution

A:
B. First off , standard form of a 2nd degree equation is Ax^2 + Bx + C. So look at the coefficient of Ax^2 which is -2.
If positive, the parabola opens up and has a minimum.
If negative, the parabola opens down and has a maximum.

A. To find the vertex (in this case maximum),
Graph the equation -OR—
make a table. — OR—
Find the zeroes and find the middle x-value
-2x^2 - 4x + 6
-2(x^2 +2x - 3 = 0
-2 (x - 1) ( x + 3)=0
x - 1 = 0. x + 3 = 0
x = 1. x = -3. So halfway would be at (-1, __).
Sub in -1 into original equation -2x^2 -4x + 6 … -2(-1)^2 -4(-1) + 6 = -2 +4 +6 = 8
So the vertex is (-1,8)