X^2+6x-7=x+3+5

Solution for X^2+6x-7=x+3+5 equation:

X^2+6X-7=X+3+5

We move all terms to the left:

X^2+6X-7-(X+3+5)=0

We add all the numbers together, and all the variables

X^2+6X-(X+8)-7=0

We get rid of parentheses

X^2+6X-X-8-7=0

We add all the numbers together, and all the variables

X^2+5X-15=0

a = 1; b = 5; c = -15;
Δ = b2-4ac
Δ = 52-4·1·(-15)
Δ = 85
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-\sqrt{85}}{2*1}=\frac{-5-\sqrt{85}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{85}}{2*1}=\frac{-5+\sqrt{85}}{2}
$