3x+1.28=7/10x

Solution for 3x+1.28=7/10x equation:

3x+1.28=7/10x

We move all terms to the left:

3x+1.28-(7/10x)=0


Domain of the equation: 10x)!=0

x!=0/1

x!=0

x∈R


We add all the numbers together, and all the variables

3x-(+7/10x)+1.28=0

We get rid of parentheses

3x-7/10x+1.28=0

We multiply all the terms by the denominator


3x*10x+(1.28)*10x-7=0

We multiply parentheses

3x*10x+12.8x-7=0

Wy multiply elements

30x^2+12.8x-7=0

a = 30; b = 12.8; c = -7;
Δ = b2-4ac
Δ = 12.82-4·30·(-7)
Δ = 1003.84
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12.8)-\sqrt{1003.84}}{2*30}=\frac{-12.8-\sqrt{1003.84}}{60}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12.8)+\sqrt{1003.84}}{2*30}=\frac{-12.8+\sqrt{1003.84}}{60}
$