-5x(2x+8)=-2(5x+8)

Solution for -5x(2x+8)=-2(5x+8) equation:

-5x(2x+8)=-2(5x+8)

We move all terms to the left:

-5x(2x+8)-(-2(5x+8))=0

We multiply parentheses

-10x^2-40x-(-2(5x+8))=0


We calculate terms in parentheses: -(-2(5x+8)), so:

-2(5x+8)

We multiply parentheses

-10x-16

Back to the equation:

-(-10x-16)


We get rid of parentheses

-10x^2-40x+10x+16=0

We add all the numbers together, and all the variables

-10x^2-30x+16=0

a = -10; b = -30; c = +16;
Δ = b2-4ac
Δ = -302-4·(-10)·16
Δ = 1540
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1540}=\sqrt{4*385}=\sqrt{4}*\sqrt{385}=2\sqrt{385}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-2\sqrt{385}}{2*-10}=\frac{30-2\sqrt{385}}{-20}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+2\sqrt{385}}{2*-10}=\frac{30+2\sqrt{385}}{-20}
$