Question 244008
4x^2-8x-9=0
=> (2x)^2 - 2.2x.2 + 2^2 -9 -4 = 0
=> (2x -2)^2 = 13
=> 2x - 2 = +sqrt(13) or -sqrt(13)
=> 2x = 2 +sqrt(13) or 2-sqrt(13)
x = 1 + sqrt(13)/2 or 1 - sqrt(13)/2