x/0.3x-0.4x=-0.7

Solution for x/0.3x-0.4x=-0.7 equation:

x/0.3x-0.4x=-0.7

We move all terms to the left:

x/0.3x-0.4x-(-0.7)=0


Domain of the equation: 0.3x!=0

x!=0/0.3

x!=0

x∈R


We add all the numbers together, and all the variables

-0.4x+x/0.3x+0.7=0

We multiply all the terms by the denominator


-(0.4x)*0.3x+x+(0.7)*0.3x=0

We add all the numbers together, and all the variables

-(+0.4x)*0.3x+x+(0.7)*0.3x=0

We add all the numbers together, and all the variables

x-(+0.4x)*0.3x+(0.7)*0.3x=0

We multiply parentheses

-0x^2+x+0x=0

We add all the numbers together, and all the variables

-1x^2+2x=0

a = -1; b = 2; c = 0;
Δ = b2-4ac
Δ = 22-4·(-1)·0
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2}{2*-1}=\frac{-4}{-2}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2}{2*-1}=\frac{0}{-2}
=0
$