15x^2-70x-245=0

Solution for 15x^2-70x-245=0 equation:

15x^2-70x-245=0

a = 15; b = -70; c = -245;
Δ = b2-4ac
Δ = -702-4·15·(-245)
Δ = 19600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{19600}=140$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-70)-140}{2*15}=\frac{-70}{30}
=-2+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-70)+140}{2*15}=\frac{210}{30}
=7
$