4f+20-15/7f=26.24

Solution for 4f+20-15/7f=26.24 equation:

4f+20-15/7f=26.24

We move all terms to the left:

4f+20-15/7f-(26.24)=0


Domain of the equation: 7f!=0

f!=0/7

f!=0

f∈R


We add all the numbers together, and all the variables

4f-15/7f-6.24=0

We multiply all the terms by the denominator


4f*7f-(6.24)*7f-15=0

We multiply parentheses

4f*7f-43.68f-15=0

Wy multiply elements

28f^2-43.68f-15=0

a = 28; b = -43.68; c = -15;
Δ = b2-4ac
Δ = -43.682-4·28·(-15)
Δ = 3587.9424
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-43.68)-\sqrt{3587.9424}}{2*28}=\frac{43.68-\sqrt{3587.9424}}{56}
$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-43.68)+\sqrt{3587.9424}}{2*28}=\frac{43.68+\sqrt{3587.9424}}{56}
$