8/15c+1/5c=3/7

Solution for 8/15c+1/5c=3/7 equation:

8/15c+1/5c=3/7

We move all terms to the left:

8/15c+1/5c-(3/7)=0


Domain of the equation: 15c!=0

c!=0/15

c!=0

c∈R



Domain of the equation: 5c!=0

c!=0/5

c!=0

c∈R


We add all the numbers together, and all the variables

8/15c+1/5c-(+3/7)=0

We get rid of parentheses

8/15c+1/5c-3/7=0

We calculate fractions


(-1125c^2)/3675c^2+1960c/3675c^2+735c/3675c^2=0

We multiply all the terms by the denominator


(-1125c^2)+1960c+735c=0

We add all the numbers together, and all the variables

(-1125c^2)+2695c=0

We get rid of parentheses

-1125c^2+2695c=0

a = -1125; b = 2695; c = 0;
Δ = b2-4ac
Δ = 26952-4·(-1125)·0
Δ = 7263025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7263025}=2695$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2695)-2695}{2*-1125}=\frac{-5390}{-2250}
=2+89/225
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2695)+2695}{2*-1125}=\frac{0}{-2250}
=0
$