14=2x+3x^2

Solution for 14=2x+3x^2 equation:

14=2x+3x^2

We move all terms to the left:

14-(2x+3x^2)=0

We get rid of parentheses

-3x^2-2x+14=0

a = -3; b = -2; c = +14;
Δ = b2-4ac
Δ = -22-4·(-3)·14
Δ = 172
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:

$\sqrt{\Delta}=\sqrt{172}=\sqrt{4*43}=\sqrt{4}*\sqrt{43}=2\sqrt{43}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-2\sqrt{43}}{2*-3}=\frac{2-2\sqrt{43}}{-6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+2\sqrt{43}}{2*-3}=\frac{2+2\sqrt{43}}{-6}
$