36=a^2-5a

Solution for 36=a^2-5a equation:

36=a^2-5a

We move all terms to the left:

36-(a^2-5a)=0

We get rid of parentheses

-a^2+5a+36=0

We add all the numbers together, and all the variables

-1a^2+5a+36=0

a = -1; b = 5; c = +36;
Δ = b2-4ac
Δ = 52-4·(-1)·36
Δ = 169
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{169}=13$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-13}{2*-1}=\frac{-18}{-2}
=+9
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+13}{2*-1}=\frac{8}{-2}
=-4
$