Question

Solve : (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 + sqrt3)(x - sqrt3) = 0`

if  `x + sqrt13 = 0` or `x- sqrt13 = 0`

`=> x = -sqrt13 or x= sqrt13`