4/5x-3=3/10x=7

Solution for 4/5x-3=3/10x=7 equation:

4/5x-3=3/10x=7

We move all terms to the left:

4/5x-3-(3/10x)=0


Domain of the equation: 5x!=0

x!=0/5

x!=0

x∈R



Domain of the equation: 10x)!=0

x!=0/1

x!=0

x∈R


We add all the numbers together, and all the variables

4/5x-(+3/10x)-3=0

We get rid of parentheses

4/5x-3/10x-3=0

We calculate fractions


40x/50x^2+(-15x)/50x^2-3=0

We multiply all the terms by the denominator


40x+(-15x)-3*50x^2=0

Wy multiply elements

-150x^2+40x+(-15x)=0

We get rid of parentheses

-150x^2+40x-15x=0

We add all the numbers together, and all the variables

-150x^2+25x=0

a = -150; b = 25; c = 0;
Δ = b2-4ac
Δ = 252-4·(-150)·0
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(25)-25}{2*-150}=\frac{-50}{-300}
=1/6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+25}{2*-150}=\frac{0}{-300}
=0
$