x^2-3.75=2.5

Solution for x^2-3.75=2.5 equation:

x^2-3.75=2.5

We move all terms to the left:

x^2-3.75-(2.5)=0

We add all the numbers together, and all the variables

x^2-6.25=0

a = 1; b = 0; c = -6.25;
Δ = b2-4ac
Δ = 02-4·1·(-6.25)
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-5}{2*1}=\frac{-5}{2}
=-2+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+5}{2*1}=\frac{5}{2}
=2+1/2
$