X(3x+2)=320

Solution for X(3x+2)=320 equation:

X(3X+2)=320

We move all terms to the left:

X(3X+2)-(320)=0

We multiply parentheses

3X^2+2X-320=0

a = 3; b = 2; c = -320;
Δ = b2-4ac
Δ = 22-4·3·(-320)
Δ = 3844
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3844}=62$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-62}{2*3}=\frac{-64}{6}
=-10+2/3
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+62}{2*3}=\frac{60}{6}
=10
$