20x^2+140x-245=0

Solution for 20x^2+140x-245=0 equation:

20x^2+140x-245=0

a = 20; b = 140; c = -245;
Δ = b2-4ac
Δ = 1402-4·20·(-245)
Δ = 39200
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{39200}=\sqrt{19600*2}=\sqrt{19600}*\sqrt{2}=140\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(140)-140\sqrt{2}}{2*20}=\frac{-140-140\sqrt{2}}{40}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(140)+140\sqrt{2}}{2*20}=\frac{-140+140\sqrt{2}}{40}
$