Using the quadratic formula to solve 2x2 = 4x - 7, what are the values of x?

2x^2 - 4x + 7 = 0

a = 2, b = - 4, c = 7

x = - b + - sqrt (b^2 - 4 ac) / 2a

= 4 + - sqrt (16 - 4 * 2 * 7) / 2 * 2 = 1 + - 1/4 sqrt (16 - 56)

= 1 + - 0.25sqrt (-40) = 1 + - 0.5sqrt (10) = [2+sqrt (10) ]/2 and [2-sqrt (10) ]/2