3(-3x^2+22x-7)=0

Solution for 3(-3x^2+22x-7)=0 equation:

3(-3x^2+22x-7)=0

We multiply parentheses

-9x^2+66x-21=0

a = -9; b = 66; c = -21;
Δ = b2-4ac
Δ = 662-4·(-9)·(-21)
Δ = 3600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3600}=60$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(66)-60}{2*-9}=\frac{-126}{-18}
=+7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(66)+60}{2*-9}=\frac{-6}{-18}
=1/3
$