x^2-2.25x-7=0

Solution for x^2-2.25x-7=0 equation:

x^2-2.25x-7=0

a = 1; b = -2.25; c = -7;
Δ = b2-4ac
Δ = -2.252-4·1·(-7)
Δ = 33.0625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2.25)-\sqrt{33.0625}}{2*1}=\frac{2.25-\sqrt{33.0625}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2.25)+\sqrt{33.0625}}{2*1}=\frac{2.25+\sqrt{33.0625}}{2}
$