14a^2+58a-20=0

Solution for 14a^2+58a-20=0 equation:

14a^2+58a-20=0

a = 14; b = 58; c = -20;
Δ = b2-4ac
Δ = 582-4·14·(-20)
Δ = 4484
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{4484}=\sqrt{4*1121}=\sqrt{4}*\sqrt{1121}=2\sqrt{1121}$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(58)-2\sqrt{1121}}{2*14}=\frac{-58-2\sqrt{1121}}{28}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(58)+2\sqrt{1121}}{2*14}=\frac{-58+2\sqrt{1121}}{28}
$