7x^2+168x+105=0

Solution for 7x^2+168x+105=0 equation:

7x^2+168x+105=0

a = 7; b = 168; c = +105;
Δ = b2-4ac
Δ = 1682-4·7·105
Δ = 25284
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:

$\sqrt{\Delta}=\sqrt{25284}=\sqrt{196*129}=\sqrt{196}*\sqrt{129}=14\sqrt{129}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(168)-14\sqrt{129}}{2*7}=\frac{-168-14\sqrt{129}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(168)+14\sqrt{129}}{2*7}=\frac{-168+14\sqrt{129}}{14}
$