SOLUTION: Solve the equation by completing the square. Round to the nearest hundredth if necessary. x2 + 2x = 17

Question 1088722: Solve the equation by completing the square. Round to the nearest hundredth if necessary. x2 + 2x = 17
Found 2 solutions by natolino_2017, josmiceli:
Answer by natolino_2017(77) (Show Source): You can put this solution on YOUR website!
First remember the formula: (x+a)^2 = x^2 + 2ax + a^2.
so (x+1)^2 = x^2 + 2x + 1.
using this on x^2 + 2x = 17

(x+1)^2 - 1 = 17
(x+1)^2 = 18
abs(x+1) = sqrt(18) = 3sqrt(2)
so x = -1 +3sqrt(2) or x = -1 -3sqrt(2)
aproaching to the nearest hundreth:
x={3.24;-5.24}
@natolino_
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!

Take 1/2 of the x term, square it,
and add it to both sides

--------------------------------

and, taking the negative square root:

--------------------------
check:

OK
You can check the other solution

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