13=y2+5y=

Solution for 13=y2+5y= equation:

13=y2+5y=

We move all terms to the left:

13-(y2+5y)=0

We add all the numbers together, and all the variables

-(+y^2+5y)+13=0

We get rid of parentheses

-y^2-5y+13=0

We add all the numbers together, and all the variables

-1y^2-5y+13=0

a = -1; b = -5; c = +13;
Δ = b2-4ac
Δ = -52-4·(-1)·13
Δ = 77
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-\sqrt{77}}{2*-1}=\frac{5-\sqrt{77}}{-2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+\sqrt{77}}{2*-1}=\frac{5+\sqrt{77}}{-2}
$