17^2=8^2+b^2

Solution for 17^2=8^2+b^2 equation:

17^2=8^2+b^2

We move all terms to the left:

17^2-(8^2+b^2)=0

We add all the numbers together, and all the variables

-(8^2+b^2)+289=0

We get rid of parentheses

-b^2+289-8^2=0

We add all the numbers together, and all the variables

-1b^2+225=0

a = -1; b = 0; c = +225;
Δ = b2-4ac
Δ = 02-4·(-1)·225
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-30}{2*-1}=\frac{-30}{-2}
=+15
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+30}{2*-1}=\frac{30}{-2}
=-15
$