## Katlyn99 2 years ago Which ordered pairs from the replacement set are solutions to the equation? y = -2x + 9 ; Replacement Set {((-1, 11), (0, 8), (1, 7), (2, 5)} (-1, 11) (0, 8) (1, 7) (2, 5)

1. tcarroll010

Each ordered pair is of the form:\[(x _{1}, y _{1})\]You take each ordered pair and substitute like so:\[y _{1} = -2x _{1} + 9\]and see if it is true. You do this for each ordered pair, one at a time and test it. For your first ordered pair, the x1 = -1 and the y1 = 11. So, you can test the first one by substituting those values.

2. tcarroll010

So you ask yourself if: 11 = -2(-1) + 9 is true or not.

3. tcarroll010

What is -2(-1) ? Hint: that is -2 times -1

4. Katlyn99

2

5. Katlyn99

so -1,11 works

6. tcarroll010

To perform multiplication with negative signs, you first multiply the numbers and then if the number of "-" signs is an even number, you have a positive result. Just saw your answer, so you probably already understand this. Good. So, continuing: 11 = -2(-1) + 9 -> 11 = 2 + 9 Yes, you already saw now that it works. Good job. Now just check the other 3 ordered pairs. Hint: only one doesn't work.

7. Katlyn99

ok thanks:)

8. tcarroll010

So, this is making sense to you now?

9. Katlyn99

yes it is I just needed a refresher

10. tcarroll010

I'm glad you're getting this. It's a great feeling when understanding comes. It's like a gift.

11. tcarroll010

Good luck again and thx for the recognition!