0.6=(x+10)(2x+10)

Solution for 0.6=(x+10)(2x+10) equation:

0.6=(x+10)(2x+10)

We move all terms to the left:

0.6-((x+10)(2x+10))=0

We multiply parentheses ..

-((+2x^2+10x+20x+100))+0.6=0


We calculate terms in parentheses: -((+2x^2+10x+20x+100)), so:

(+2x^2+10x+20x+100)

We get rid of parentheses

2x^2+10x+20x+100

We add all the numbers together, and all the variables

2x^2+30x+100

Back to the equation:

-(2x^2+30x+100)


We get rid of parentheses

-2x^2-30x-100+0.6=0

We add all the numbers together, and all the variables

-2x^2-30x-99.4=0

a = -2; b = -30; c = -99.4;
Δ = b2-4ac
Δ = -302-4·(-2)·(-99.4)
Δ = 104.8
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{-(-30)-\sqrt{104.8}}{2*-2}=\frac{30-\sqrt{104.8}}{-4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+\sqrt{104.8}}{2*-2}=\frac{30+\sqrt{104.8}}{-4}
$