Solve by Factoring 3x^3-6x^2-9x=0

$3 x^{3} - 6 x^{2} - 9 x = 0$

Step 1

Factor $3 x$ out of $3 x^{3} - 6 x^{2} - 9 x$ .

Factor $3 x$ out of $3 x^{3}$ .

$3 x (x^{2}) - 6 x^{2} - 9 x = 0$

Factor $3 x$ out of $- 6 x^{2}$ .

$3 x (x^{2}) + 3 x (- 2 x) - 9 x = 0$

Factor $3 x$ out of $- 9 x$ .

$3 x (x^{2}) + 3 x (- 2 x) + 3 x (- 3) = 0$

Factor $3 x$ out of $3 x (x^{2}) + 3 x (- 2 x)$ .

$3 x (x^{2} - 2 x) + 3 x (- 3) = 0$

Factor $3 x$ out of $3 x (x^{2} - 2 x) + 3 x (- 3)$ .

$3 x (x^{2} - 2 x - 3) = 0$

Step 2

Factor.

Factor $x^{2} - 2 x - 3$ using the AC method.

Consider the form $x^{2} + b x + c$ . Find a pair of integers whose product is $c$ and whose sum is $b$ . In this case, whose product is $- 3$ and whose sum is $- 2$ .

$- 3, 1$

Write the factored form using these integers.

$3 x ((x - 3) (x + 1)) = 0$

Remove unnecessary parentheses.

$3 x (x - 3) (x + 1) = 0$

Step 3

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$x = 0$

$x - 3 = 0$

$x + 1 = 0$

Step 4

Set $x$ equal to $0$ .

$x = 0$

Step 5

Set $x - 3$ equal to $0$ and solve for $x$ .

Set $x - 3$ equal to $0$ .

$x - 3 = 0$

Add $3$ to both sides of the equation.

$x = 3$

Step 6

Set $x + 1$ equal to $0$ and solve for $x$ .

Set $x + 1$ equal to $0$ .

$x + 1 = 0$

Subtract $1$ from both sides of the equation.

$x = - 1$

Step 7

The final solution is all the values that make $3 x (x - 3) (x + 1) = 0$ true.

$x = 0, 3, - 1$

Solve by Factoring 3x^3-6x^2-9x=0

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