1. Subtracting Polynomials

2. Lets review Copy the following expressions and then write the opposite of each one. 1. 2y 2 -3 2. 3x 2 +5x-4 3. -2m 2 -m+3

3. Check your answer. 1. 2y 2 -3 2. 3x 2 +5x-4 -3x 2 -5x+4 3. -2m 2 -m+3 2m 2 +m-3 - 2y 2 +3

4. Subtraction We learned that subtraction means to add the opposite when we were studying integers. We need to remember this as we study subtraction of polynomials as well.

5. The vertical form is usually easier to use when subtracting polynomials. Example: (3x-1)-(2x+2) 3x-1 Rewrite 3x-1 -(2x+2) and add -2x-2 -(2x+2) and add -2x-2 x-3 x-3

6. Of course, the idea of changing signs and adding can be used in the horizontal form too. Example: (3x-1)-(2x+2) = (3x-1)+(-2x-2) = 3x-1-2x-2 = 3x-1-2x-2 = x-3 = x-3

7. Copy these on your paper and work them. 1.) (7x+3) - (4x-6) 2.) (3x-3y) – (4x-7y) 3.) (5a 2 +2a) – (-2a 2 -17)

8. Check your answers 1.) (7x+3) - (4x-6) = 3x+9 2.) (3x-3y) – (4x-7y) = -x+4y 3.) (5a 2 +2a) – (-2a 2 -17) = 7a 2 +2a-17