Quadratic Function Complete square

Question

−2x2+8x+10=0

I can go part way, but get stuck. Any advice on how to complete squares in general is also helpful!

Answer 1

-2(x² - 4x ) + 10 = 0

-2(x² - 4x + 4) + 10 + 8 = 0

-2(x - 2)² + 18 = 0

-2(x - 2)² = - 18

(x - 2)² = 9

x - 2 = ±3

Answer 2

−2x² + 8x + 10 = 0

Move the 10 to the other side:

−2x² + 8x = -10

Divide both sides by -2:

x² - 4x = 5

This is the key step: to each side add one half of the coefficient of the x term (-4) divided by 2, then squared: (-4/2)^2. This turns the left side of the equation into a perfect square:

x² - 4x + (-4/2)² = 5 + (-4/2)²

x² - 4x + 4 = 5 + 4

(x - 2)² = 9 [ (x-2)² is the perfect square ]

x-2 = ± 3

x = 2 ± 3

x = 2 + 3 = 5 and x = 2 - 3 = -1

Two answers, x = 3 and x = -1