(-5+6.25a)+10a*10)=a

Solution for (-5+6.25a)+10a*10)=a equation:

(-5+6.25a)+10a*10)=a

We move all terms to the left:

(-5+6.25a)+10a*10)-(a)=0

We add all the numbers together, and all the variables

(6.25a-5)+10a*10)-a=0

Wy multiply elements

100a^2+(6.25a-5)=0

We get rid of parentheses

100a^2+6.25a-5=0

a = 100; b = 6.25; c = -5;
Δ = b2-4ac
Δ = 6.252-4·100·(-5)
Δ = 2039.0625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6.25)-\sqrt{2039.0625}}{2*100}=\frac{-6.25-\sqrt{2039.0625}}{200}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6.25)+\sqrt{2039.0625}}{2*100}=\frac{-6.25+\sqrt{2039.0625}}{200}
$