# How do you solve # c^2+6c-27=0# by completing the square?

##### 1 Answer

May 7, 2015

The answer is

Solve

**Add #27# to both sides.**

**Halve the coefficient of #6c# then square it.**

**Add #9# to both sides of the equation.**

**The lefthand side of the equation is now a perfect trinomial square. Factor the perfect trinomial square. #a^2+2ab+b^2=(a+b)^2#**

**Take the square root of both sides and solve for #c#.**

**When #c+3=6#:**

**When #c+3=-6#:**

**Check:**

Reference: http://www.regentsprep.org/regents/math/algtrig/ate12/completesqlesson.htm