6x^2-21x=-18

Solution for 6x^2-21x=-18 equation:

6x^2-21x=-18

We move all terms to the left:

6x^2-21x-(-18)=0

We add all the numbers together, and all the variables

6x^2-21x+18=0

a = 6; b = -21; c = +18;
Δ = b2-4ac
Δ = -212-4·6·18
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-3}{2*6}=\frac{18}{12}
=1+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+3}{2*6}=\frac{24}{12}
=2
$