(6x-15)(x+8)=

Solution for (6x-15)(x+8)= equation:

(6x-15)(x+8)=

We move all terms to the left:

(6x-15)(x+8)-()=0

We add all the numbers together, and all the variables

(6x-15)(x+8)=0

We multiply parentheses ..

(+6x^2+48x-15x-120)=0

We get rid of parentheses

6x^2+48x-15x-120=0

We add all the numbers together, and all the variables

6x^2+33x-120=0

a = 6; b = 33; c = -120;
Δ = b2-4ac
Δ = 332-4·6·(-120)
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{-(33)-63}{2*6}=\frac{-96}{12}
=-8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(33)+63}{2*6}=\frac{30}{12}
=2+1/2
$