How do you complete the square to solve #-2x^2 - 7x + 4 = 0#?
NOTE. This method of completing the squares is unadvised when b is an odd number and a is negative. Completing the squares in this case is very challenging and easy to make errors/mistakes.
Solving by the new Transforming method (Google, Yahoo Search) is a lot simpler.
y = -(2x^2 + 7x - 4) = 0 (1)
y' = -(x^2 + 7x - 8) (2) -> a.c = -8 --> factor: (-1, 8) -> sum = b
Two real roots of (2): 1 and -8
Two real roots of (1): 1/2 and -4