How do you solve using the completing the square method #x^2+6x=7#?

1 Answer
Apr 18, 2016

Answer:

Create a perfect square trinomial on the left side, and your solution is not far away!

Explanation:

First, the lead coefficient should = 1 to make this easiest.
Then, take half of the linear coefficient, then square it. Add to both sides:
#x^2+6x+9=7+9#
Factor the left:
#(x+3)^2=16#
Take the square root of both sides:
#sqrt((x+3)^2)=sqrt(16)#
Left side inverse operations undo each other, on the right side, don't forget the #+-# on the right!

#x+3=+-4#

so #x + 3 = 4# or #x + 3 = -4#

so x = 1 or -7.