7x^2-144x-72=0

Solution for 7x^2-144x-72=0 equation:

7x^2-144x-72=0

a = 7; b = -144; c = -72;
Δ = b2-4ac
Δ = -1442-4·7·(-72)
Δ = 22752
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:

$\sqrt{\Delta}=\sqrt{22752}=\sqrt{144*158}=\sqrt{144}*\sqrt{158}=12\sqrt{158}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-144)-12\sqrt{158}}{2*7}=\frac{144-12\sqrt{158}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-144)+12\sqrt{158}}{2*7}=\frac{144+12\sqrt{158}}{14}
$