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36 votes
36 votes
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01:28:2
solve x2 + 12x = -11 by completing the square. which is the solution set of the equation?
be
o {-11, -1}
o {-11, 1}
{11, -1}
o {11, 1}

User Masashi M
by
3.3k points

2 Answers

22 votes
22 votes

Answer:

11

Explanation:

User Vishal Khode
by
2.6k points
19 votes
19 votes
First, make the equation equal to zero:
x^2 + 12x + 11 = 0

then complete the square
(x + 6)^2 - 36 + 11 = 0
(x + 6)^2 - 25 =0

(x + 6)^2 = 25

take the square root of both sides

(x + 6) = 5 or (x + 6) = -5

then, isolate x,

x = -1 or x = -11
User Caulitomaz
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2.5k points