(8-c)(9/8-c)=9

Solution for (8-c)(9/8-c)=9 equation:

(8-c)(9/8-c)=9

We move all terms to the left:

(8-c)(9/8-c)-(9)=0


Domain of the equation: 8-c)!=0

We move all terms containing c to the left, all other terms to the right

-c)!=-8

c!=-8/1

c!=-8

c∈R


We add all the numbers together, and all the variables

(-1c+8)(-1c+9/8)-9=0

We multiply parentheses ..

(+c^2-9c^2-8c+8*9/8)-9=0

We multiply all the terms by the denominator


(+c^2-9c^2-8c+8*9-9*8)=0

We get rid of parentheses

c^2-9c^2-8c+8*9-9*8=0

We add all the numbers together, and all the variables

-8c^2-8c=0

a = -8; b = -8; c = 0;
Δ = b2-4ac
Δ = -82-4·(-8)·0
Δ = 64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{64}=8$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-8}{2*-8}=\frac{0}{-16}
=0
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+8}{2*-8}=\frac{16}{-16}
=-1
$