3x^2-6x-140=0

Solution for 3x^2-6x-140=0 equation:

3x^2-6x-140=0

a = 3; b = -6; c = -140;
Δ = b2-4ac
Δ = -62-4·3·(-140)
Δ = 1716
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:

$\sqrt{\Delta}=\sqrt{1716}=\sqrt{4*429}=\sqrt{4}*\sqrt{429}=2\sqrt{429}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-2\sqrt{429}}{2*3}=\frac{6-2\sqrt{429}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+2\sqrt{429}}{2*3}=\frac{6+2\sqrt{429}}{6}
$