2x(4x+5)=-2

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

2x(4x+5)=-2

We move all terms to the left:

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

We add all the numbers together, and all the variables

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

We multiply parentheses

8x^2+10x+2=0

a = 8; b = 10; c = +2;
Δ = b2-4ac
Δ = 102-4·8·2
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-6}{2*8}=\frac{-16}{16}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+6}{2*8}=\frac{-4}{16}
=-1/4
$