1. Objectives
Simplify expressions with several variables by combining like terms.

2. Glossary Terms Coefficient Variable Exponent Term Like Terms
Simplified

3. Like Terms – same variable with same exponent
Key Skills
Like Terms – same variable with same exponent
Simplify
When combining like terms, only use the coefficients.
6x + 2x =
6x + 2x = 8x
Simplify
4x + 3y – 2x + 4y =
2x + 7y
Never, NEVER, combine x’s and y’s or constant terms with variable terms. 2x + 7y ≠ 9xy and 3a + 6 ≠ 9a.

4. + 7x 7x + 3y + 3y + 5y + 5y + 9x + 9x – 6y – 6y = 16x 16x = +2y + 2y
Just Watch What Happens
+ 7x 7x
+ 3y
+ 3y
+ 5y
+ 5y
+ 9x
+ 9x
– 6y
– 6y
= 16x
16x
= +2y
+ 2y

5. 3 + 5x = 3 + 5x ≠ 8x 3(5x) = 15x TRY THESE 1) 3q + 7q = 10q
Your welcome
2) 4x + 8y – 10x + 3y =
4x + 8y + 10x + 3y =
14x + 11y
Review Again
3 + 5x = 3 + 5x
≠ 8x
3(5x) =
15x

6. In algebraic terms, find the perimeter of the following shape.
4x + 3y
Key Skills
3x – 2y
3x – 2y
4x + 3y
To find the perimeter, add the sides together.
P = 3x – 2y + 4x +3y + 3x – 2y + 4x + 3y =
14x + 2y
What is the perimeter if x = 3 and y = 2?
P = 14(3) + 2(2) = 46

7. Find the perimeter of the following shape when x = 2.
TRY THIS
5x + y
5x + y
6x – 2y
To find the perimeter, add the sides together.
P = 5x + y + 5x + y + 6x – 2y =
16x = 32
Does the value of y matter in this problem?
Obviously Not!