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

Solution for 2(x+3)(x-11)=0 equation:

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

We multiply parentheses ..

2(+x^2-11x+3x-33)=0

We multiply parentheses

2x^2-22x+6x-66=0

We add all the numbers together, and all the variables

2x^2-16x-66=0

a = 2; b = -16; c = -66;
Δ = b2-4ac
Δ = -162-4·2·(-66)
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-28}{2*2}=\frac{-12}{4}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+28}{2*2}=\frac{44}{4}
=11
$