How do you solve the equation #x^2+2x-6=0# by completing the square?
1 Answer
Dec 24, 2016
Explanation:
The difference of squares identity can be written:
#a^2-b^2 = (a-b)(a+b)#
Use this with
#0 = x^2+2x-6#
#color(white)(0) = x^2+2x+1-7#
#color(white)(0) = (x+1)^2-(sqrt(7))^2#
#color(white)(0) = ((x+1)-sqrt(7))((x+1)+sqrt(7))#
#color(white)(0) = (x+1-sqrt(7))(x+1+sqrt(7))#
Hence:
#x = -1+-sqrt(7)#
