7/10c+1/5c=8/9

Solution for 7/10c+1/5c=8/9 equation:

7/10c+1/5c=8/9

We move all terms to the left:

7/10c+1/5c-(8/9)=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

7/10c+1/5c-(+8/9)=0

We get rid of parentheses

7/10c+1/5c-8/9=0

We calculate fractions


(-2000c^2)/4050c^2+2835c/4050c^2+810c/4050c^2=0

We multiply all the terms by the denominator


(-2000c^2)+2835c+810c=0

We add all the numbers together, and all the variables

(-2000c^2)+3645c=0

We get rid of parentheses

-2000c^2+3645c=0

a = -2000; b = 3645; c = 0;
Δ = b2-4ac
Δ = 36452-4·(-2000)·0
Δ = 13286025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{13286025}=3645$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3645)-3645}{2*-2000}=\frac{-7290}{-4000}
=1+329/400
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3645)+3645}{2*-2000}=\frac{0}{-4000}
=0
$