-2x^2+4x+3=0
Complete square
Quadratic equation
-2x^2+4x+3=0
divide each term by -2 and move the constant to the right side at the same time
x^2 - 2x = 3/2
add the missing constant, which completes the square to both sides
x^2 - 2x + 1 = 3/2 + 1
factor it
(x-1)^2 = 5/2 or 10/4
x-1 = ±√10/2
x = 1 ± √10/2 or (2 ± √10)/2