12=-2.7x^2+30x+6.5

Solution for 12=-2.7x^2+30x+6.5 equation:

12=-2.7x^2+30x+6.5

We move all terms to the left:

12-(-2.7x^2+30x+6.5)=0

We get rid of parentheses

2.7x^2-30x-6.5+12=0

We add all the numbers together, and all the variables

2.7x^2-30x+5.5=0

a = 2.7; b = -30; c = +5.5;
Δ = b2-4ac
Δ = -302-4·2.7·5.5
Δ = 840.6
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-\sqrt{840.6}}{2*2.7}=\frac{30-\sqrt{840.6}}{5.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+\sqrt{840.6}}{2*2.7}=\frac{30+\sqrt{840.6}}{5.4}
$