(x+1)(3x-11)=0

Solution for (x+1)(3x-11)=0 equation:

(x+1)(3x-11)=0

We multiply parentheses ..

(+3x^2-11x+3x-11)=0

We get rid of parentheses

3x^2-11x+3x-11=0

We add all the numbers together, and all the variables

3x^2-8x-11=0

a = 3; b = -8; c = -11;
Δ = b2-4ac
Δ = -82-4·3·(-11)
Δ = 196
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{196}=14$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-14}{2*3}=\frac{-6}{6}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+14}{2*3}=\frac{22}{6}
=3+2/3
$