3x(2x+5)=3x+4x

Solution for 3x(2x+5)=3x+4x equation:

3x(2x+5)=3x+4x

We move all terms to the left:

3x(2x+5)-(3x+4x)=0

We add all the numbers together, and all the variables

3x(2x+5)-(+7x)=0

We multiply parentheses

6x^2+15x-(+7x)=0

We get rid of parentheses

6x^2+15x-7x=0

We add all the numbers together, and all the variables

6x^2+8x=0

a = 6; b = 8; c = 0;
Δ = b2-4ac
Δ = 82-4·6·0
Δ = 64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{64}=8$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-8}{2*6}=\frac{-16}{12}
=-1+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+8}{2*6}=\frac{0}{12}
=0
$