Answer:
D = -4
E = 2
Step-by-step explanation:
The procedure for completing the square method is given as:
x2 + bx + c = 0
x2 + bx = -c
x2 + bx + (b/2)2 = -c + (b/2)2
Aolving the LHS simultaneously,
(x + b)2 = -c + (b/2)2
Find the square root of both sides,
(x + b) = sqrt(-c + (b/2)2)
So for the equation, x2 - 8x + 12
x2 - 8x = -12
x2 - 8x + 16 = -12 + 16
(x - 4)2 = 4
So square root both sides,
(x - 4) = 2
Comparing this to the equation given,
(x - D) = E;
D = -4
E = 2
