1/2y-4=1/9y

Solution for 1/2y-4=1/9y equation:

1/2y-4=1/9y

We move all terms to the left:

1/2y-4-(1/9y)=0


Domain of the equation: 2y!=0

y!=0/2

y!=0

y∈R



Domain of the equation: 9y)!=0

y!=0/1

y!=0

y∈R


We add all the numbers together, and all the variables

1/2y-(+1/9y)-4=0

We get rid of parentheses

1/2y-1/9y-4=0

We calculate fractions


9y/18y^2+(-2y)/18y^2-4=0

We multiply all the terms by the denominator


9y+(-2y)-4*18y^2=0

Wy multiply elements

-72y^2+9y+(-2y)=0

We get rid of parentheses

-72y^2+9y-2y=0

We add all the numbers together, and all the variables

-72y^2+7y=0

a = -72; b = 7; c = 0;
Δ = b2-4ac
Δ = 72-4·(-72)·0
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-7}{2*-72}=\frac{-14}{-144}
=7/72
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+7}{2*-72}=\frac{0}{-144}
=0
$