B=(5x-3)(x+6)

Solution for B=(5x-3)(x+6) equation:

=(5B-3)(B+6)

We move all terms to the left:

-((5B-3)(B+6))=0

We multiply parentheses ..

-((+5B^2+30B-3B-18))=0


We calculate terms in parentheses: -((+5B^2+30B-3B-18)), so:

(+5B^2+30B-3B-18)

We get rid of parentheses

5B^2+30B-3B-18

We add all the numbers together, and all the variables

5B^2+27B-18

Back to the equation:

-(5B^2+27B-18)


We get rid of parentheses

-5B^2-27B+18=0

a = -5; b = -27; c = +18;
Δ = b2-4ac
Δ = -272-4·(-5)·18
Δ = 1089
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$B_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$B_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1089}=33$
$B_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-27)-33}{2*-5}=\frac{-6}{-10}
=3/5
$
$B_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-27)+33}{2*-5}=\frac{60}{-10}
=-6
$