Download Lesson 2

LESSON 2.7 Day 2
Combining Like Terms
Goal: Simplify expressions by combining like terms.
Warm-up:
Write the additive inverse (the opposite) for the following numbers:
1)
2
3
2) -5
3)
19
Write the multiplicative inverse (the reciprocal) for the following numbers:
4)
2
3
5) -5
6)
19
Match the letter of the property with the math sentence.
7) 18 + 7 = 7 + 18
A) Associative Property
8) -45.3 + 45.3 = 0
B) Identity Property of Addition
9) 5 4 =1
4 5
C) Inverse Property of Multiplication
D) Commutative Property
10) a * (b * c) = (a * b) * c
E) Inverse Property of Addition
11) -20 + 0 = -20
12) For the following expressions, identify the terms, like terms, coefficients and constant terms.
-5x + 4 - x - 13
Rewrite as addition: _______________________________
Terms:
Like terms:
Coefficients:
x - 3 - 3x + 12
Constants:
Rewrite as addition: _______________________________
Terms:
Coefficients:
Like terms:
Constants:
13) Combine Like Terms:
A) -2x + 3y + 7x – 10
B) -7 –(4a) + 5b -10a
C) 3n – 4n + 7n – m
D) 17x – (-4x) + 5y – (-10y)
EXAMPLE 1 – Combining Like Terms with Multiple Variables
Remember: Like terms are terms that have the same variables with THE SAME EXPONENTS!
a) 2xy  5x + 8xy  3x
b) 3y + 2xy – y + 4
c) 4x²y + 5x²y + 4xy
Now YOU try it: Combine the like terms:
1) -2 + 5x – 4xy – 7y
2) -3xy + 2y + 7y – 7
5)
-3xy² - 4xy² - y
2