(3x-2)(x+7)=156

Solution for (3x-2)(x+7)=156 equation:

(3x-2)(x+7)=156

We move all terms to the left:

(3x-2)(x+7)-(156)=0

We multiply parentheses ..

(+3x^2+21x-2x-14)-156=0

We get rid of parentheses

3x^2+21x-2x-14-156=0

We add all the numbers together, and all the variables

3x^2+19x-170=0

a = 3; b = 19; c = -170;
Δ = b2-4ac
Δ = 192-4·3·(-170)
Δ = 2401
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2401}=49$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(19)-49}{2*3}=\frac{-68}{6}
=-11+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+49}{2*3}=\frac{30}{6}
=5
$