Answer:
(x+1)² = 7
Explanation:
Given the expression
-2x = x² - 6
Rewrite
x² - 6 + 2x = 0
x²+2x-6 = 0
Add 6 to both sides
x²+2x-6+6 = 0+6
x²+2x = 6
Add square of half of coefficient of x to both sides
Coefficient of x = 2
Half of Coefficient of x = 2/2 = 1
Square of half of Coefficient of x = 1² = 1
Add 1 to both sides
x²+2x + 1= 6 + 1
Factorize the LHS
x²+x+x + 1 = 7
x(x+1)+1(x+1) = 7
(x+1)(x+1) = 7
(x+1)² = 7
hence the equation rewritten by completing the square method is
(x+1)² = 7