(3x+7)*(x-11)=0

Solution for (3x+7)*(x-11)=0 equation:

(3x+7)(x-11)=0

We multiply parentheses ..

(+3x^2-33x+7x-77)=0

We get rid of parentheses

3x^2-33x+7x-77=0

We add all the numbers together, and all the variables

3x^2-26x-77=0

a = 3; b = -26; c = -77;
Δ = b2-4ac
Δ = -262-4·3·(-77)
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-26)-40}{2*3}=\frac{-14}{6}
=-2+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-26)+40}{2*3}=\frac{66}{6}
=11
$