Warm-Up Combine Like Terms: 6x + 2y - 3x + 4y -3z + 4x -5y + 2z

COMBINING LIKE TERMS

LIKE TERMS Terms that have the same variable part or “last name” but differ only in their numerical coefficients “Last Name” Part -4x2y 7x2y coefficient coefficient

COMBINING LIKE TERMS -2ab + 4a + 7ab – 6a You can only add or subtract terms that have exactly the same variable part or “last name.” -2ab + 4a + 7ab – 6a

-2ab + 4a + 7ab – 6a -2ab + 7ab = 5ab 4a – 6a = -2a 5ab – 2a COMBINE LIKE TERMS Make sure you take the sign to the left of each term when you combine them. -2ab + 7ab = 5ab 4a – 6a = -2a 5ab – 2a

NOW YOU TRY IT! -9 – 4x2 + 6x – y – 8x + 3y -4x2 – 2x + 2y - 9 -4x2

TEST YOURSELF 1) 7s – 9s + 7r – 10r 2) –5m – 3m2 + 8 – 6m2 3) –5 + 11a – 4b –2a + b 4) 3c – 6d + 6 + 6d – 4c 5) 2 + 5x – 8 – 7x – 9 + y

ANSWERS 1) –3r – 2s 2) –9m2 – 5m + 8 3) 9a – 3b - 5 4) –c + 6 5) –2x + y - 15

REMEMBER. . . You can only add or subtract “like terms.” Terms that have the same variable part or “last name.” When combining like terms, remember to take the sign to the left of each term.

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