3(3x-7)(x+3)=0

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

3(3x-7)(x+3)=0

We multiply parentheses ..

3(+3x^2+9x-7x-21)=0

We multiply parentheses

9x^2+27x-21x-63=0

We add all the numbers together, and all the variables

9x^2+6x-63=0

a = 9; b = 6; c = -63;
Δ = b2-4ac
Δ = 62-4·9·(-63)
Δ = 2304
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2304}=48$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-48}{2*9}=\frac{-54}{18}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+48}{2*9}=\frac{42}{18}
=2+1/3
$