1/2x+9=4/5x

Solution for 1/2x+9=4/5x equation:

1/2x+9=4/5x

We move all terms to the left:

1/2x+9-(4/5x)=0


Domain of the equation: 2x!=0

x!=0/2

x!=0

x∈R



Domain of the equation: 5x)!=0

x!=0/1

x!=0

x∈R


We add all the numbers together, and all the variables

1/2x-(+4/5x)+9=0

We get rid of parentheses

1/2x-4/5x+9=0

We calculate fractions


5x/10x^2+(-8x)/10x^2+9=0

We multiply all the terms by the denominator


5x+(-8x)+9*10x^2=0

Wy multiply elements

90x^2+5x+(-8x)=0

We get rid of parentheses

90x^2+5x-8x=0

We add all the numbers together, and all the variables

90x^2-3x=0

a = 90; b = -3; c = 0;
Δ = b2-4ac
Δ = -32-4·90·0
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-3}{2*90}=\frac{0}{180}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+3}{2*90}=\frac{6}{180}
=1/30
$