Y=(-5x-1)(2x+8)

Solution for Y=(-5x-1)(2x+8) equation:

=(-5Y-1)(2Y+8)

We move all terms to the left:

-((-5Y-1)(2Y+8))=0

We multiply parentheses ..

-((-10Y^2-40Y-2Y-8))=0


We calculate terms in parentheses: -((-10Y^2-40Y-2Y-8)), so:

(-10Y^2-40Y-2Y-8)

We get rid of parentheses

-10Y^2-40Y-2Y-8

We add all the numbers together, and all the variables

-10Y^2-42Y-8

Back to the equation:

-(-10Y^2-42Y-8)


We get rid of parentheses

10Y^2+42Y+8=0

a = 10; b = 42; c = +8;
Δ = b2-4ac
Δ = 422-4·10·8
Δ = 1444
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1444}=38$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(42)-38}{2*10}=\frac{-80}{20}
=-4
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(42)+38}{2*10}=\frac{-4}{20}
=-1/5
$