2x(x-6)=140

Solution for 2x(x-6)=140 equation:

2x(x-6)=140

We move all terms to the left:

2x(x-6)-(140)=0

We multiply parentheses

2x^2-12x-140=0

a = 2; b = -12; c = -140;
Δ = b2-4ac
Δ = -122-4·2·(-140)
Δ = 1264
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:

$\sqrt{\Delta}=\sqrt{1264}=\sqrt{16*79}=\sqrt{16}*\sqrt{79}=4\sqrt{79}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-4\sqrt{79}}{2*2}=\frac{12-4\sqrt{79}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+4\sqrt{79}}{2*2}=\frac{12+4\sqrt{79}}{4}
$