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Question
Solve equation using factorisation method:
(x + 1)(2x + 8) = (x + 7)(x + 3)
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Solution
(x + 1)(2x + 8) = (x + 7)(x + 3)
⇒ 2x2 + 8x + 2x + 8 = x2 + 3x + 7x + 21
⇒ 2x2 + 10x + 8 = x2 + 10x + 21
⇒ x2 – 13 = 0
⇒ `x^2 - (sqrt13)^2 = 0`
⇒ `(x + sqrt13)(x -sqrt13) = 0`
If `x + sqrt13 = 0` or `x - sqrt13 = 0`
⇒ `x = -sqrt13` or `x = sqrt13`
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