X(x+7)=-6x+8

Solution for X(x+7)=-6x+8 equation:

X(X+7)=-6X+8

We move all terms to the left:

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

We multiply parentheses

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

We get rid of parentheses

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

We add all the numbers together, and all the variables

X^2+13X-8=0

a = 1; b = 13; c = -8;
Δ = b2-4ac
Δ = 132-4·1·(-8)
Δ = 201
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{-(13)-\sqrt{201}}{2*1}=\frac{-13-\sqrt{201}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+\sqrt{201}}{2*1}=\frac{-13+\sqrt{201}}{2}
$