-(4/5)f+1=-13

Solution for -(4/5)f+1=-13 equation:

-(4/5)f+1=-13

We move all terms to the left:

-(4/5)f+1-(-13)=0


Domain of the equation: 5)f!=0

f!=0/1

f!=0

f∈R


We add all the numbers together, and all the variables

-(+4/5)f+1-(-13)=0

We add all the numbers together, and all the variables

-(+4/5)f+14=0

We multiply parentheses

-4f^2+14=0

a = -4; b = 0; c = +14;
Δ = b2-4ac
Δ = 02-4·(-4)·14
Δ = 224
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{224}=\sqrt{16*14}=\sqrt{16}*\sqrt{14}=4\sqrt{14}$
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{14}}{2*-4}=\frac{0-4\sqrt{14}}{-8}
=-\frac{4\sqrt{14}}{-8}
=-\frac{\sqrt{14}}{-2}
$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{14}}{2*-4}=\frac{0+4\sqrt{14}}{-8}
=\frac{4\sqrt{14}}{-8}
=\frac{\sqrt{14}}{-2}
$