x^2-12.5x-3.5=0

Solution for x^2-12.5x-3.5=0 equation:

x^2-12.5x-3.5=0

a = 1; b = -12.5; c = -3.5;
Δ = b2-4ac
Δ = -12.52-4·1·(-3.5)
Δ = 170.25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12.5)-\sqrt{170.25}}{2*1}=\frac{12.5-\sqrt{170.25}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12.5)+\sqrt{170.25}}{2*1}=\frac{12.5+\sqrt{170.25}}{2}
$