## bleumom22 2 years ago Solve X+Y= 1 X-Y= 7

1. ashlynn143

there has to be like one

2. ashlynn143

3. ashlynn143

to the variables

4. ashlynn143

is that the whole question ???

5. incomplte

Its a simultaenous equation do you have any ideas?

6. bleumom22

yes thats the whole question the + equation is on top of the - equation

7. ashlynn143

oh i hate question like this

8. bleumom22

I don't have a clue it all looks foriegn to me. I looked through my notes and I see nothing similar to this problem.

9. ashlynn143

yah i've learned some really tough things and i have never done something like this

10. incomplte

Start by\[X=1-Y\] Plug that into the second eqn

11. bleumom22

ok but htne there aren't any values for the the other equations do I'm suiming it has to be a negative number. someone told me for a similar problem with one negative answer and one positive answer I could add both equations and then muliplty the result and substitute it for either varible to find the other. it worked for that problem but not for this one wwhere both answers are positive

12. bleumom22

then*

13. ashlynn143

well if it is like how @incomplte said then i have the answer but if it is like how you are saying then i dont know

14. bleumom22

ok ill try it his way but im still coming up blank

15. ashlynn143

ok for the second one it is 1 - (-7)

16. ashlynn143

AND YOU WOULD GET ????

17. bleumom22

8

18. incomplte

Eqn 2 becomes\[(1-Y)-Y = 7\] So1-2Y=7 -2Y=6 Y=-3

19. ashlynn143

correct @bleumom22 see now you get for #2

20. incomplte

Can you solve for X now?

21. bleumom22

just substitiue for y and then ill get the x variable?

22. incomplte

Good. Let me know what you get for X

23. bleumom22

ok x=4?

24. incomplte

Yes.

25. ashlynn143

good job

26. bleumom22

im sorry can you tell me the first step to solving this.

27. incomplte

28. bleumom22

I have two exams next week and need to remember this.

29. incomplte

Just start by Solving for X So from X+Y=1, say X=1-Y then plug that into the second equation.

30. bleumom22

oooh. ok and then just input the answer for one of the variables then divide the varible by its self and the answer by its self to get the variable's value?

31. bleumom22

as one of the varibles* to reverse calculate?

32. incomplte

Yes. If you have any more questions just @ my username. Ill get a notification and i can help later

33. ashlynn143

and i will try to help you if you need it ok

34. bleumom22

ok thank you to @incomplte and @ashlynn143

35. ashlynn143

your welcome i gtg for like 15 min