2.5c+4-1/5c=-9

Solution for 2.5c+4-1/5c=-9 equation:

2.5c+4-1/5c=-9

We move all terms to the left:

2.5c+4-1/5c-(-9)=0


Domain of the equation: 5c!=0

c!=0/5

c!=0

c∈R


We add all the numbers together, and all the variables

2.5c-1/5c+13=0

We multiply all the terms by the denominator


(2.5c)*5c+13*5c-1=0

We add all the numbers together, and all the variables

(+2.5c)*5c+13*5c-1=0

We multiply parentheses

10c^2+13*5c-1=0

Wy multiply elements

10c^2+65c-1=0

a = 10; b = 65; c = -1;
Δ = b2-4ac
Δ = 652-4·10·(-1)
Δ = 4265
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(65)-\sqrt{4265}}{2*10}=\frac{-65-\sqrt{4265}}{20}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(65)+\sqrt{4265}}{2*10}=\frac{-65+\sqrt{4265}}{20}
$