### Home > CCA2 > Chapter 6 > Lesson 6.1.5 > Problem6-85

6-85.

Use the correct method from problem 6-84 to change each of the following equations to graphing form. Then, without graphing, find the vertex and equation of the line of symmetry for each.

1. $y=2x^2−8x+7$

Complete the square to find the equation.

$y=2(x^2−4x+4)+7−8$

Use $y=a(x−h)^2+k$ and $(h,k)$ to find the vertex and axis of symmetry.

$y=2(x−2)^2−1$

vertex: $(2,−1)$
axis of symmetry: $x=2$

2. $y=5x^2−10x−7$

See part (a).

$y=5(x−1)^2−12$
vertex: $(1,−12)$
axis of symmetry: $x=1$