Solve by factoring: (x+6)(x-2)=9?

x ² + 4 x - 12 = 9
x ² + 4 x - 21 = 0
( x + 7 ) ( x - 3 ) = 0
x = - 7 , x = 3

(x + 6)(x - 2) = 9
x² + 6x - 2x - 12 = 9
x² + 4x - 12 = 9
x² + 4x - 21 = 0
(x - 3)(x + 7)
x - 3 = 0, x = 3
x + 7 = 0, x = - 7

Answer: x = 3 or x = - 7

Just checking my work:
(3 + 6)(3 - 2) = 9
9 * 1 = 9

(- 7 + 6)(- 7 - 2) = 9
- 1 * - 9 = 9

In order to use the multiplicative property of zero, you have to have the factored polynomial set equal to zero. Since this is not the case, we have to multiply these binomials, make sure the equation is set equal to zero. Then we can re-factor and solve.

(x + 6)(x - 2) = 9
x^2 + 6x - 2x - 12 = 9
x^2 + 4x - 12 = 9

Subtract 9 from both sides.
x^2 + 4x - 21 = 0

Now we re-factor.
(x + 7)(x - 3) = 0

Either of these factors could equal zero to make the multiplication of them equal zero.

x + 7 = 0 ..... OR ..... x - 3 = 0
x = -7 ..... OR ..... x = 3

x^2+6x-2x-12 = 9
x^2+4x-12 = 9
x^2+4x-21 = 0
(x+7)(x-3) = 0
So, x= -7,x= 3

Use a carat ^ to show powers. in any different case, it seems such as you're multiplying via 2 instead of squaring it. (x - 3)^2 = 9 (FOIL) x^2 - 6x + 9 = 9 (subtract 9 from the two aspects) x^2 - 6x = 0 (component out x) x(x - 6) = 0 (0-product sources) x = 0 or x - 6 = 0 x = 0 or x = 6 <===answer or you may additionally sparkling up it like this: (x - 3)^2 = 9 (sq. root the two aspects) x - 3 = +/- 3 x - 3 = 3 or x - 3 = -3 x = 6 or x = 0

(x + 6)(x - 2) = 9
x^2 + 6x - 2x - 12 = 9
x^2 + 4x - 21 = 0
(x + 7)(x - 3) = 0
x = -7 or 3

(x+6)(x-2)=9
x^2 + 4x - 12 = 9
x^2 + 4x - 21 = 0
(x + 7)(x - 3) = 0
x = -7 or 3

You have to expand the left hand side of the equation first, i.e.,

x^2 + 4x -12 = 9

Subtracting 9 from each side of the equation

x^2 + 4x - 12 - 9 = 9 - 9
x^2 + 4x - 21 = 0

Factor the above and you get,

(x + 7)(X-3) = 0

x = 3 and x = -7

First it factors out to be (x^2)-4x-12=9
Then you subtract 9 from both sides and it equals
(x^2)-4x-21=0
Then you factor again (x-7)(x+3)=0
Then x-7=0 and x+3=0 and x=7,3

You've got the factoring already. Now just solve for x.
x+6=9, x-2=9
x=3, x=11