Y=2(x-1)(x+7)

Solution for Y=2(x-1)(x+7) equation:

=2(Y-1)(Y+7)

We move all terms to the left:

-(2(Y-1)(Y+7))=0

We multiply parentheses ..

-(2(+Y^2+7Y-1Y-7))=0


We calculate terms in parentheses: -(2(+Y^2+7Y-1Y-7)), so:

2(+Y^2+7Y-1Y-7)

We multiply parentheses

2Y^2+14Y-2Y-14

We add all the numbers together, and all the variables

2Y^2+12Y-14

Back to the equation:

-(2Y^2+12Y-14)


We get rid of parentheses

-2Y^2-12Y+14=0

a = -2; b = -12; c = +14;
Δ = b2-4ac
Δ = -122-4·(-2)·14
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-16}{2*-2}=\frac{-4}{-4}
=1
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+16}{2*-2}=\frac{28}{-4}
=-7
$