(10+2a)(26-19);a=2

Solution for (10+2a)(26-19);a=2 equation:

(10+2a)(26-19)a=2

We move all terms to the left:

(10+2a)(26-19)a-(2)=0

We add all the numbers together, and all the variables

(2a+10)7a-2=0

We multiply parentheses

14a^2+70a-2=0

a = 14; b = 70; c = -2;
Δ = b2-4ac
Δ = 702-4·14·(-2)
Δ = 5012
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{5012}=\sqrt{4*1253}=\sqrt{4}*\sqrt{1253}=2\sqrt{1253}$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(70)-2\sqrt{1253}}{2*14}=\frac{-70-2\sqrt{1253}}{28}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(70)+2\sqrt{1253}}{2*14}=\frac{-70+2\sqrt{1253}}{28}
$