3/4x-7/20=2/5x

Solution for 3/4x-7/20=2/5x equation:

3/4x-7/20=2/5x

We move all terms to the left:

3/4x-7/20-(2/5x)=0


Domain of the equation: 4x!=0

x!=0/4

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

3/4x-(+2/5x)-7/20=0

We get rid of parentheses

3/4x-2/5x-7/20=0

We calculate fractions


(-700x^2)/800x^2+600x/800x^2+(-320x)/800x^2=0

We multiply all the terms by the denominator


(-700x^2)+600x+(-320x)=0

We get rid of parentheses

-700x^2+600x-320x=0

We add all the numbers together, and all the variables

-700x^2+280x=0

a = -700; b = 280; c = 0;
Δ = b2-4ac
Δ = 2802-4·(-700)·0
Δ = 78400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{78400}=280$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(280)-280}{2*-700}=\frac{-560}{-1400}
=2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(280)+280}{2*-700}=\frac{0}{-1400}
=0
$