(3x+2)(x)=80

Solution for (3x+2)(x)=80 equation:

(3x+2)(x)=80

We move all terms to the left:

(3x+2)(x)-(80)=0

We multiply parentheses

3x^2+2x-80=0

a = 3; b = 2; c = -80;
Δ = b2-4ac
Δ = 22-4·3·(-80)
Δ = 964
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:

$\sqrt{\Delta}=\sqrt{964}=\sqrt{4*241}=\sqrt{4}*\sqrt{241}=2\sqrt{241}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2\sqrt{241}}{2*3}=\frac{-2-2\sqrt{241}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2\sqrt{241}}{2*3}=\frac{-2+2\sqrt{241}}{6}
$