Collecting Like Terms

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 identicalliteral 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