Finite Math Examples

$3 x^{2} + 21 x = 0$

Step 1

Factor $3 x$ out of $3 x^{2} + 21 x$ .

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Step 1.1

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

$3 x (x) + 21 x = 0$

Step 1.2

Factor $3 x$ out of $21 x$ .

$3 x (x) + 3 x (7) = 0$

Step 1.3

Factor $3 x$ out of $3 x (x) + 3 x (7)$ .

$3 x (x + 7) = 0$

Step 2

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

$x = 0$

$x + 7 = 0$

Step 3

Set $x$ equal to $0$ .

$x = 0$

Step 4

Set $x + 7$ equal to $0$ and solve for $x$ .

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Step 4.1

Set $x + 7$ equal to $0$ .

$x + 7 = 0$

Step 4.2

Subtract $7$ from both sides of the equation.

$x = - 7$

Step 5

The final solution is all the values that make $3 x (x + 7) = 0$ true.

$x = 0, - 7$

Step 6