9a2+5a=-7a

Solution for 9a2+5a=-7a equation:

9a^2+5a=-7a

We move all terms to the left:

9a^2+5a-(-7a)=0

We get rid of parentheses

9a^2+5a+7a=0

We add all the numbers together, and all the variables

9a^2+12a=0

a = 9; b = 12; c = 0;
Δ = b2-4ac
Δ = 122-4·9·0
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*9}=\frac{-24}{18}
=-1+1/3
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+12}{2*9}=\frac{0}{18}
=0
$