A=12(b1+b2)

Solution for A=12(b1+b2) equation:

=12(A1+A2)

We move all terms to the left:

-(12(A1+A2))=0

We add all the numbers together, and all the variables

-(12(+A+A^2))=0


We calculate terms in parentheses: -(12(+A+A^2)), so:

12(+A+A^2)

We multiply parentheses

12A^2+12A

Back to the equation:

-(12A^2+12A)


We get rid of parentheses

-12A^2-12A=0

a = -12; b = -12; c = 0;
Δ = b2-4ac
Δ = -122-4·(-12)·0
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-12}{2*-12}=\frac{0}{-24}
=0
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+12}{2*-12}=\frac{24}{-24}
=-1
$