B(x)=x^2-36

Solution for B(x)=x^2-36 equation:

(B)=B^2-36

We move all terms to the left:

(B)-(B^2-36)=0

We get rid of parentheses

-B^2+B+36=0

We add all the numbers together, and all the variables

-1B^2+B+36=0

a = -1; b = 1; c = +36;
Δ = b2-4ac
Δ = 12-4·(-1)·36
Δ = 145
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$B_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$B_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$B_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-\sqrt{145}}{2*-1}=\frac{-1-\sqrt{145}}{-2}
$
$B_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{145}}{2*-1}=\frac{-1+\sqrt{145}}{-2}
$