(3f-1)(f-7)=0

Solution for (3f-1)(f-7)=0 equation:

(3f-1)(f-7)=0

We multiply parentheses ..

(+3f^2-21f-1f+7)=0

We get rid of parentheses

3f^2-21f-1f+7=0

We add all the numbers together, and all the variables

3f^2-22f+7=0

a = 3; b = -22; c = +7;
Δ = b2-4ac
Δ = -222-4·3·7
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-22)-20}{2*3}=\frac{2}{6}
=1/3
$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-22)+20}{2*3}=\frac{42}{6}
=7
$