(5b+1)(6b+1)=0

Solution for (5b+1)(6b+1)=0 equation:

(5b+1)(6b+1)=0

We multiply parentheses ..

(+30b^2+5b+6b+1)=0

We get rid of parentheses

30b^2+5b+6b+1=0

We add all the numbers together, and all the variables

30b^2+11b+1=0

a = 30; b = 11; c = +1;
Δ = b2-4ac
Δ = 112-4·30·1
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(11)-1}{2*30}=\frac{-12}{60}
=-1/5
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(11)+1}{2*30}=\frac{-10}{60}
=-1/6
$