Question

Solve the following quadratic equations by factorization: 

(x + 1) (2x + 8) = (x+7) (x+3) 

Answer 1

(x + 1) (2x + 8) = (x+7) (x+3)
⟹` 2x^2 + 8x + 2x + 8 = x^2 + 3x + 7x + 21`
⟹` 2x^2 + 10x + 8 = x^2 + 10x + 21`
⟹` x^2 – 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`