(X-11)(5x+8)=0

Solution for (X-11)(5x+8)=0 equation:

(X-11)(5X+8)=0

We multiply parentheses ..

(+5X^2+8X-55X-88)=0

We get rid of parentheses

5X^2+8X-55X-88=0

We add all the numbers together, and all the variables

5X^2-47X-88=0

a = 5; b = -47; c = -88;
Δ = b2-4ac
Δ = -472-4·5·(-88)
Δ = 3969
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3969}=63$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-47)-63}{2*5}=\frac{-16}{10}
=-1+3/5
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-47)+63}{2*5}=\frac{110}{10}
=11
$