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## anonymous one year ago can somebody help me plot these constraints

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1. anonymous

$x+y \le12$

2. freckles

do you know how to graph the line y=-x+12?

3. anonymous

nope

4. freckles

do you know how to find y when x=-1? or do you know how to find y when x=1?

5. anonymous

no

6. freckles

what is y when x=-1? replace x with -1 and find out like so: y=-(-1)+12 evaluate/simplify what is y when x=1? replace x with 1 and find out like so: y=-(1)+12 evaluate/simplify

7. freckles

If you aren't sure what I'm asking, I'm asking you to do the following: Evaluate -(-1)+12 and Evaluate -1+12

8. anonymous

11

9. freckles

-1+12=11 but -(-1)+12=1+12=13 so when x=-1 you have y=-(-1)+12=13 and so when x=1 you have y=-(1)+12=-1+12=11 So you can graph the ordered pairs (-1,13) and (1,11) as a start to plotting the line. Then once we have the line we have to work with the inequality part.

10. freckles

|dw:1434654369343:dw| plotted the points not just connect the dots and extend your line passed the dots

11. freckles

|dw:1434654419427:dw|

12. anonymous

is it both of them or only one

13. freckles

now your inequality said: $x+y \le 12 \\ \text{ subtracting the } x \text{ on both says } y \le -x+12 \\ \text{ and that is why I graphed the line } y=-x+12$ now you already have the equal part of your inequality. Now y<-x+12 means you want to shade below your line.

14. freckles

what do you mean?

15. freckles

I plotted both points.

16. freckles

and connected the dots.

17. freckles

do you know why we shade below the line for y<-x+12? It is because that represents all the ordered pairs with a y value less than any point that falls on the line.

18. anonymous

i got it now thanks very much

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