0.15-0.2x=0.3x(x+5)

Solution for 0.15-0.2x=0.3x(x+5) equation:

0.15-0.2x=0.3x(x+5)

We move all terms to the left:

0.15-0.2x-(0.3x(x+5))=0


We calculate terms in parentheses: -(0.3x(x+5)), so:

0.3x(x+5)

We multiply parentheses

0x^2+0x

We add all the numbers together, and all the variables

x^2+x

Back to the equation:

-(x^2+x)


We get rid of parentheses

-x^2-0.2x-x+0.15=0

We add all the numbers together, and all the variables

-1x^2-1.2x+0.15=0

a = -1; b = -1.2; c = +0.15;
Δ = b2-4ac
Δ = -1.22-4·(-1)·0.15
Δ = 2.04
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{-(-1.2)-\sqrt{2.04}}{2*-1}=\frac{1.2-\sqrt{2.04}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.2)+\sqrt{2.04}}{2*-1}=\frac{1.2+\sqrt{2.04}}{-2}
$