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

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

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

We add all the numbers together, and all the variables

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

We multiply parentheses ..

(-9x^2-21x+21x+49)=0

We get rid of parentheses

-9x^2-21x+21x+49=0

We add all the numbers together, and all the variables

-9x^2+49=0

a = -9; b = 0; c = +49;
Δ = b2-4ac
Δ = 02-4·(-9)·49
Δ = 1764
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1764}=42$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-42}{2*-9}=\frac{-42}{-18}
=2+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+42}{2*-9}=\frac{42}{-18}
=-2+1/3
$