2x2+30x-87,5=0

Solution for 2x2+30x-87,5=0 equation:

2x^2+30x-87.5=0

a = 2; b = 30; c = -87.5;
Δ = b2-4ac
Δ = 302-4·2·(-87.5)
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-40}{2*2}=\frac{-70}{4}
=-17+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+40}{2*2}=\frac{10}{4}
=2+1/2
$