2^2+b^2=2.5^2

Solution for 2^2+b^2=2.5^2 equation:

2^2+b^2=2.5^2

We move all terms to the left:

2^2+b^2-(2.5^2)=0

We add all the numbers together, and all the variables

b^2-2.25=0

a = 1; b = 0; c = -2.25;
Δ = b2-4ac
Δ = 02-4·1·(-2.25)
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-3}{2*1}=\frac{-3}{2}
=-1+1/2
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+3}{2*1}=\frac{3}{2}
=1+1/2
$