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Given the equation 2x+5=11, How would I multiply each side by ( x+2 )?

 Feb 4, 2017
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Expand the following:
(x + 2) (2 x + 5) = 11 (x + 2)

(x + 2) (2 x + 5) = (x) (2 x) + (x) (5) + (2) (2 x) + (2) (5) = 2 x^2 + 5 x + 4 x + 10 = 2 x^2 + 9 x + 10:
2 x^2 + 9 x + 10 = 11 (x + 2)

11 (x + 2) = 11 x + 11 2:
2 x^2 + 9 x + 10 = 11 x + 11 2

11×2 = 22:
2 x^2 + 9 x + 10 = 11 x + 22

Subtract 11 x + 22 from both sides of 2 x^2 + 9 x + 10 = 11 x + 22:
2 x^2 + 9 x - 11 x + 22 + 10 = (11 x + 22) - 11 x + 22

(11 x + 22) - (11 x + 22) = 0:
2 x^2 + 9 x - (11 x + 22) + 10 = 0

-(11 x + 22) = -22 - 11 x:
2 x^2 + 9 x + -22 - 11 x + 10 = 0

Grouping like terms, 2 x^2 + 9 x - 11 x - 22 + 10 = 2 x^2 + (9 x - 11 x) + (10 - 22):
2 x^2 + (9 x - 11 x) + (10 - 22) = 0

9 x - 11 x = -2 x:
2 x^2 + -2 x + (10 - 22) = 0

10 - 22 = -12:
Answer: |2 x^2 - 2 x + -12 = 0

 Feb 4, 2017

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