-5x(-7-4x)=-2(3x-4)

Solution for -5x(-7-4x)=-2(3x-4) equation:

-5x(-7-4x)=-2(3x-4)

We move all terms to the left:

-5x(-7-4x)-(-2(3x-4))=0

We add all the numbers together, and all the variables

-5x(-4x-7)-(-2(3x-4))=0

We multiply parentheses

20x^2+35x-(-2(3x-4))=0


We calculate terms in parentheses: -(-2(3x-4)), so:

-2(3x-4)

We multiply parentheses

-6x+8

Back to the equation:

-(-6x+8)


We get rid of parentheses

20x^2+35x+6x-8=0

We add all the numbers together, and all the variables

20x^2+41x-8=0

a = 20; b = 41; c = -8;
Δ = b2-4ac
Δ = 412-4·20·(-8)
Δ = 2321
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{-(41)-\sqrt{2321}}{2*20}=\frac{-41-\sqrt{2321}}{40}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(41)+\sqrt{2321}}{2*20}=\frac{-41+\sqrt{2321}}{40}
$