0=-2.7x^2+30x-15.5

Solution for 0=-2.7x^2+30x-15.5 equation:

0=-2.7x^2+30x-15.5

We move all terms to the left:

0-(-2.7x^2+30x-15.5)=0

We add all the numbers together, and all the variables

-(-2.7x^2+30x-15.5)=0

We get rid of parentheses

2.7x^2-30x+15.5=0

a = 2.7; b = -30; c = +15.5;
Δ = b2-4ac
Δ = -302-4·2.7·15.5
Δ = 732.6
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{732.6}}{2*2.7}=\frac{30-\sqrt{732.6}}{5.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+\sqrt{732.6}}{2*2.7}=\frac{30+\sqrt{732.6}}{5.4}
$