9a=10a^2

Solution for 9a=10a^2 equation:

9a=10a^2

We move all terms to the left:

9a-(10a^2)=0

determiningTheFunctionDomain
-10a^2+9a=0

a = -10; b = 9; c = 0;
Δ = b2-4ac
Δ = 92-4·(-10)·0
Δ = 81
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{81}=9$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-9}{2*-10}=\frac{-18}{-20}
=9/10
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+9}{2*-10}=\frac{0}{-20}
=0
$