169=25+b^2

Solution for 169=25+b^2 equation:

169=25+b^2

We move all terms to the left:

169-(25+b^2)=0

We get rid of parentheses

-b^2-25+169=0

We add all the numbers together, and all the variables

-1b^2+144=0

a = -1; b = 0; c = +144;
Δ = b2-4ac
Δ = 02-4·(-1)·144
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-24}{2*-1}=\frac{-24}{-2}
=+12
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+24}{2*-1}=\frac{24}{-2}
=-12
$