(f+4)(2f-6)=0

Solution for (f+4)(2f-6)=0 equation:

(f+4)(2f-6)=0

We multiply parentheses ..

(+2f^2-6f+8f-24)=0

We get rid of parentheses

2f^2-6f+8f-24=0

We add all the numbers together, and all the variables

2f^2+2f-24=0

a = 2; b = 2; c = -24;
Δ = b2-4ac
Δ = 22-4·2·(-24)
Δ = 196
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{196}=14$
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-14}{2*2}=\frac{-16}{4}
=-4
$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+14}{2*2}=\frac{12}{4}
=3
$