12-7a(2)+5a=12-9a

Solution for 12-7a(2)+5a=12-9a equation:

12-7a(2)+5a=12-9a

We move all terms to the left:

12-7a(2)+5a-(12-9a)=0

We add all the numbers together, and all the variables

-7a2+5a-(-9a+12)+12=0

We add all the numbers together, and all the variables

-7a^2+5a-(-9a+12)+12=0

We get rid of parentheses

-7a^2+5a+9a-12+12=0

We add all the numbers together, and all the variables

-7a^2+14a=0

a = -7; b = 14; c = 0;
Δ = b2-4ac
Δ = 142-4·(-7)·0
Δ = 196
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{196}=14$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(14)-14}{2*-7}=\frac{-28}{-14}
=+2
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(14)+14}{2*-7}=\frac{0}{-14}
=0
$