## anonymous 5 years ago identify the point of intersection, using one of the following methods: Elimination, subsitiution, graphing X starts at 0 and goes up by 10 each rep for up to 15 reps To find y for the first its .4(X)+50 To find y for the second line its 4.4(X)+0

1. myininaya

what is rep?

2. anonymous

repetition so it goes up by 10 15 times

3. myininaya

so are you saying the equations are: y=.4x+50 and y=4.4x ?

4. anonymous

yes

5. myininaya

ok yes so i don't have to read that rep stuff lol

6. anonymous

idk but its within 8-12 bottles

7. anonymous

yes its 10 bottles bottles are the item we are making a graph on and x = bottles

8. anonymous

no its not ten =0

9. myininaya

just set 4.4x=.4x+50 4.4x-.4x=50 4x=50 x=50/4 x=25/2 so y=4.4x=4.4(25/2)=44/10(25/2)=22/5(25/2)=5(11)=55 so they intersect at (25/2,55)

10. anonymous

what?

11. anonymous

12. myininaya

to find where they intersect all i did was set the two lines equal to each other i want to find the x when the two lines are the same (so the equal sign means that) and i solved for x and then it didn;t matter which line i used after that to find y both lines would give me the same y

13. myininaya

yes i just replaced that one y with y=4.4x substitution

14. anonymous

would i get full credit for expaining work also what is the function of the two

15. myininaya

in the directions about it said to find the intersection it is (25/2,55) i don't know what you mean by the function of the two?

16. anonymous

ok its function for 1st line and function for 2 and if the points matter two of them from each are (1) 10,52 20,54 (2) 10,44 20, 88

17. anonymous

18. anonymous

ok while hes looking at mine ill help u

19. myininaya

wait are you saying for the first line the some of the ordered pairs are {(10,52),(20,54)} 2nd line {(10,44),{20,88)} ?

20. anonymous

by the scale they gave us these are for each 10 bottles but for the second part which i started the question it is ok because plugin them into a graph got around what you said.

21. anonymous

we were told to go by 10

22. myininaya

the above are some of the ordered pairs on the line right? you are trying to get me to check your lines, correct?

23. anonymous

the function is what im clueless about and i think it has some relation with that right?

24. myininaya

are the following ordered pairs on a line: (10,52) and (20,54) are the following ordered pairs on the other line: (10,44) and (20,88)?

25. anonymous

yes

26. anonymous

So?

27. myininaya

ok so since we know two points on the first line, the slope is $\frac{54-52}{20-10}=\frac{2}{10}=\frac{1}{5}$ so we have y=1/5*x+b we need to know the y-intercept which we are calling b in the line before we know a point on the line (10,52) x=10 and y=52 so 52=1/5*10+b we can solve for b 52=2+b 50=b so the equation of line 1 is y=1/5*x+50 now second line we know two points on it as well so we can find the slope the slope is $\frac{88-44}{20-10}=\frac{44}{10}=\frac{22}{5}$ so we have y=22/5*x+b we know a point on this line so we can find the y-intercept which we called b in the line before x=10 y=44 44=22/5*10+b so we can solve for b 44=22(2)+b 44=44+b b=0 so the equation of the line is y=22/5*x

28. myininaya

so we have Line 1: y=1/5*x+50 and Line 2: y=22/5*x 22/5*x=1/5*x+50 (by substitution) 22/5*x-1/5*x=50 21/5*x=50 x=50*5/21 x=250/21

29. myininaya

so y=22/5*250/21=1100/21

30. anonymous

so the 25/2,55 changed?

31. myininaya

so the point of intersection is (250/21,1100/21)

32. myininaya

yes we have different lines so the point of intersection will be different

33. anonymous

are you sure its not closer because on the graph i made its near the start

34. myininaya

? i found the lines by the ordered pairs you gave me those ordered pairs lie on those two lines right with (10,52) and (20,54) lying on one line and with (10,44) and (20,88) lying on the other?

35. anonymous

yea but 10 is 10 of x you can plug 1,2,3,- 150