(3b-5)(2b+5)=

Solution for (3b-5)(2b+5)= equation:

(3b-5)(2b+5)=

We move all terms to the left:

(3b-5)(2b+5)-()=0

We add all the numbers together, and all the variables

(3b-5)(2b+5)=0

We multiply parentheses ..

(+6b^2+15b-10b-25)=0

We get rid of parentheses

6b^2+15b-10b-25=0

We add all the numbers together, and all the variables

6b^2+5b-25=0

a = 6; b = 5; c = -25;
Δ = b2-4ac
Δ = 52-4·6·(-25)
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-25}{2*6}=\frac{-30}{12}
=-2+1/2
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+25}{2*6}=\frac{20}{12}
=1+2/3
$