3x^2-21x=20

Solution for 3x^2-21x=20 equation:

3x^2-21x=20

We move all terms to the left:

3x^2-21x-(20)=0

a = 3; b = -21; c = -20;
Δ = b2-4ac
Δ = -212-4·3·(-20)
Δ = 681
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{-(-21)-\sqrt{681}}{2*3}=\frac{21-\sqrt{681}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+\sqrt{681}}{2*3}=\frac{21+\sqrt{681}}{6}
$