Question

`8x^2-14x-15=0`

Answer 1

`8x^2-14x-15=0` 

⇒`16x^2-28x-30=0` 

⇒`16x^2-28x=30` 

⇒`(4x)^2-2xx4x xx7/2+(7/2)^2=30+(7/2)^2` 

⇒`(4x-7/2)^2=30+49/4=169/4=(13/2)^2` 

⇒`4x-7/2=+-13/2` 

⇒`4x=7/2=13/2  or  4x-7/2=13/2` 

⇒`4x=13/2+7/2=20/2=10  or  4x=-13/2+7/2=6/2=-3` 

⇒`x=5/2  or  x=-3/4` 

Hence, `5/2  and  -3/4` are the roots of the given equation.