(7b-2)(2b+1)=0

Solution for (7b-2)(2b+1)=0 equation:

(7b-2)(2b+1)=0

We multiply parentheses ..

(+14b^2+7b-4b-2)=0

We get rid of parentheses

14b^2+7b-4b-2=0

We add all the numbers together, and all the variables

14b^2+3b-2=0

a = 14; b = 3; c = -2;
Δ = b2-4ac
Δ = 32-4·14·(-2)
Δ = 121
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{121}=11$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3)-11}{2*14}=\frac{-14}{28}
=-1/2
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+11}{2*14}=\frac{8}{28}
=2/7
$