Y=-2(x-7)(x+9)

Solution for Y=-2(x-7)(x+9) equation:

=-2(Y-7)(Y+9)

We move all terms to the left:

-(-2(Y-7)(Y+9))=0

We multiply parentheses ..

-(-2(+Y^2+9Y-7Y-63))=0


We calculate terms in parentheses: -(-2(+Y^2+9Y-7Y-63)), so:

-2(+Y^2+9Y-7Y-63)

We multiply parentheses

-2Y^2-18Y+14Y+126

We add all the numbers together, and all the variables

-2Y^2-4Y+126

Back to the equation:

-(-2Y^2-4Y+126)


We get rid of parentheses

2Y^2+4Y-126=0

a = 2; b = 4; c = -126;
Δ = b2-4ac
Δ = 42-4·2·(-126)
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-32}{2*2}=\frac{-36}{4}
=-9
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+32}{2*2}=\frac{28}{4}
=7
$