Pre-Algebra Examples

x^{2} + 3 x + - 2 x^{2} + 9 x + 5

$x^{2} + 3 x + - 2 x^{2} + 9 x + 5$

Step 1

Replace all occurrences of

+

$+$

-

$-$ with a single

-

$-$ . A plus sign followed by a minus sign has the same mathematical meaning as a single minus sign because

1 \cdot - 1 = - 1

$1 \cdot - 1 = - 1$

x^{2} + 3 x - 2 x^{2} + 9 x + 5

$x^{2} + 3 x - 2 x^{2} + 9 x + 5$

Step 2

Subtract

2 x^{2}

$2 x^{2}$ from

x^{2}

$x^{2}$ .

- x^{2} + 3 x + 9 x + 5

$- x^{2} + 3 x + 9 x + 5$

Step 3

Add

3 x

$3 x$ and

9 x

$9 x$ .

- x^{2} + 12 x + 5

$- x^{2} + 12 x + 5$

$x^{2} + 3 x + - 2 x^{2} + 9 x + 5$

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