X=9-4y/7y

Solution for X=9-4y/7y equation:

X=9-4X/7X

We move all terms to the left:

X-(9-4X/7X)=0


Domain of the equation: 7X)!=0

X!=0/1

X!=0

X∈R


We add all the numbers together, and all the variables

X-(-4X/7X+9)=0

We get rid of parentheses

X+4X/7X-9=0

We multiply all the terms by the denominator


X*7X+4X-9*7X=0

We add all the numbers together, and all the variables

4X+X*7X-9*7X=0

Wy multiply elements

7X^2+4X-63X=0

We add all the numbers together, and all the variables

7X^2-59X=0

a = 7; b = -59; c = 0;
Δ = b2-4ac
Δ = -592-4·7·0
Δ = 3481
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3481}=59$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-59)-59}{2*7}=\frac{0}{14}
=0
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-59)+59}{2*7}=\frac{118}{14}
=8+3/7
$