### Home > A2C > Chapter 7 > Lesson 7.1.5 > Problem 7-84

7-84.

Use the correct method from problem 7-83 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. Homework Help ✎

*y*= 2*x*^{2}− 8*x*+ 7*y*= 5^{2}− 10*x*− 7

Complete the square to find the equation.

*y* = 2(*x*^{2} − 4*x* + 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

See part (a).

*y* = 5(*x* − 1)^{2} − 12

vertex: (1, −12)

axis of symmetry: *x* = 1