c^2-15c+13=-6c

Solution for c^2-15c+13=-6c equation:

c^2-15c+13=-6c

We move all terms to the left:

c^2-15c+13-(-6c)=0

We get rid of parentheses

c^2-15c+6c+13=0

We add all the numbers together, and all the variables

c^2-9c+13=0

a = 1; b = -9; c = +13;
Δ = b2-4ac
Δ = -92-4·1·13
Δ = 29
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-\sqrt{29}}{2*1}=\frac{9-\sqrt{29}}{2}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+\sqrt{29}}{2*1}=\frac{9+\sqrt{29}}{2}
$