(2+x)(2+5x)=0

Solution for (2+x)(2+5x)=0 equation:

(2+x)(2+5x)=0

We add all the numbers together, and all the variables

(x+2)(5x+2)=0

We multiply parentheses ..

(+5x^2+2x+10x+4)=0

We get rid of parentheses

5x^2+2x+10x+4=0

We add all the numbers together, and all the variables

5x^2+12x+4=0

a = 5; b = 12; c = +4;
Δ = b2-4ac
Δ = 122-4·5·4
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{-(12)-8}{2*5}=\frac{-20}{10}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+8}{2*5}=\frac{-4}{10}
=-2/5
$