How do you complete the square to solve #x^2+x=19/4#?
2 Answers
Jun 12, 2017
#x=-1/2+sqrt5#
#x=-1/2-sqrt5#
Explanation:
Given -
#x^2+x=19/4#
#x^2+x+1/4=19/4+1/4=(19+1)/4=20/4#
#(x+1/2)^2= 20/4#
#(x+1/2)=+-sqrt (20/4)=+-(sqrt5xxcancelsqrt(4))/cancelsqrt(4)#
#x+1/2=+-sqrt 5#
#x=-1/2+sqrt5#
#x=-1/2-sqrt5#
Jun 12, 2017
Explanation:
Remember the identity
or
Hence to complete square we must add
or
or
and using the identity
Hence either
or