Algebra Examples

$3 x^{2} + 8 x - - 9 x^{2} + 3 x - 8$

Step 1

Replace all occurrences of $-$ $-$ with a single $+$ . Two consecutive minus signs have the same mathematical meaning as a single plus sign because $- 1 \cdot - 1 = 1$

$3 x^{2} + 8 x + 9 x^{2} + 3 x - 8$

Step 2

Add $3 x^{2}$ and $9 x^{2}$ .

$12 x^{2} + 8 x + 3 x - 8$

Step 3

Add $8 x$ and $3 x$ .

$12 x^{2} + 11 x - 8$