(x+.8)(x+1.6)=0

Solution for (x+.8)(x+1.6)=0 equation:

(x+.8)(x+1.6)=0

We add all the numbers together, and all the variables

(x+0.8)(x+1.6)=0

We multiply parentheses ..

(+x^2+1.6x+0.8x+1.28)=0

We get rid of parentheses

x^2+1.6x+0.8x+1.28=0

We add all the numbers together, and all the variables

x^2+2.4x+1.28=0

a = 1; b = 2.4; c = +1.28;
Δ = b2-4ac
Δ = 2.42-4·1·1.28
Δ = 0.64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2.4)-\sqrt{0.64}}{2*1}=\frac{-2.4-\sqrt{0.64}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.4)+\sqrt{0.64}}{2*1}=\frac{-2.4+\sqrt{0.64}}{2}
$