1. Collecting Like Terms
Lesson 21

2. Terms
Literal Coefficients – are variables (letters) that represent unknown numbers.
Numerical coefficients – are numbers
Terms – are made up of numerical and literal coefficients.

3. Like Terms Terms with identical literal coefficients are like terms.
EXAMPLE:
y, 3y, -2y are like terms
x, -2g, 3k are not like terms
Basically the variable has to be the same.

4. Like Terms
Also the variable needs to be to the same power to be like terms.
Example:
y2, -2y2, 45y2 are like terms
y, -20y2, 5y3 are not like terms
The exponent has to be the same number.

5. Try These
Which are like terms? Why?
5b, 3g, -2g, 2g2, 5g, ½g, -g

6. Solution: Which are like terms? Why? 5b, 3g, -2g, 2g2, 5g, ½g, -g
Red – like terms. ( they all have the same variable to the same power)
White – not like terms.

7. Combining Like Terms t + t + t+ t + t
There are five variables which are like terms therefore we simply add them like we would if they were numbers.
t + t + t+ t + t = 5t

8. Combining Like Terms 4t + 3t + t = (4+3+1)t = 8t 2t2 + 8 – 5t2
Rearrange the variables so that all like terms are side by side.
2t2 – 5t2 + 8 ( notice that the sign in front of the number came with the number)
2t2 – 5t2 + 8 = -3t2 + 8

9. Combining Like Terms 2t + 3t2 – 2t –t2
3t2 – t2 + 2t – 2t (collecting like terms)
2t2 + 0
2t2

10. Combining like terms 3ab + 4a – 3b + 4ab – 7a + 2b
3ab + 4ab + 4a – 7a – 3b + 2b
7ab -3a – b
Finished the question because none of the variables are the same.

11. Class work
Lesson 21 - Worksheet