3(2x+0.4)=2(12x-3/5)

Solution for 3(2x+0.4)=2(12x-3/5) equation:

3(2x+0.4)=2(12x-3/5)

We move all terms to the left:

3(2x+0.4)-(2(12x-3/5))=0

We add all the numbers together, and all the variables

3(2x+0.4)-(2(+12x-3/5))=0

We multiply parentheses

6x-(2(+12x-3/5))+1.2=0

We multiply all the terms by the denominator


6x*5))-(2(+12x-3+(1.2)*5))=0

We add all the numbers together, and all the variables

12x+6x*5))-(2(=0

Wy multiply elements

30x^2+12x=0

a = 30; b = 12; c = 0;
Δ = b2-4ac
Δ = 122-4·30·0
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-12}{2*30}=\frac{-24}{60}
=-2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+12}{2*30}=\frac{0}{60}
=0
$