9/10c+1/5c=4/7

Solution for 9/10c+1/5c=4/7 equation:

9/10c+1/5c=4/7

We move all terms to the left:

9/10c+1/5c-(4/7)=0


Domain of the equation: 10c!=0

c!=0/10

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

9/10c+1/5c-(+4/7)=0

We get rid of parentheses

9/10c+1/5c-4/7=0

We calculate fractions


(-1000c^2)/2450c^2+2205c/2450c^2+490c/2450c^2=0

We multiply all the terms by the denominator


(-1000c^2)+2205c+490c=0

We add all the numbers together, and all the variables

(-1000c^2)+2695c=0

We get rid of parentheses

-1000c^2+2695c=0

a = -1000; b = 2695; c = 0;
Δ = b2-4ac
Δ = 26952-4·(-1000)·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*-1000}=\frac{-5390}{-2000}
=2+139/200
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2695)+2695}{2*-1000}=\frac{0}{-2000}
=0
$