7x(x+12)=58

Solution for 7x(x+12)=58 equation:

7x(x+12)=58

We move all terms to the left:

7x(x+12)-(58)=0

We multiply parentheses

7x^2+84x-58=0

a = 7; b = 84; c = -58;
Δ = b2-4ac
Δ = 842-4·7·(-58)
Δ = 8680
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:

$\sqrt{\Delta}=\sqrt{8680}=\sqrt{4*2170}=\sqrt{4}*\sqrt{2170}=2\sqrt{2170}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(84)-2\sqrt{2170}}{2*7}=\frac{-84-2\sqrt{2170}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(84)+2\sqrt{2170}}{2*7}=\frac{-84+2\sqrt{2170}}{14}
$