(2x-11)(x+9)=0

Solution for (2x-11)(x+9)=0 equation:

(2x-11)(x+9)=0

We multiply parentheses ..

(+2x^2+18x-11x-99)=0

We get rid of parentheses

2x^2+18x-11x-99=0

We add all the numbers together, and all the variables

2x^2+7x-99=0

a = 2; b = 7; c = -99;
Δ = b2-4ac
Δ = 72-4·2·(-99)
Δ = 841
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{841}=29$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-29}{2*2}=\frac{-36}{4}
=-9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+29}{2*2}=\frac{22}{4}
=5+1/2
$