## Inopeki 3 years ago Can someone teach me systems of equations?

1. agdgdgdgwngo

a linear system is simply a set of linear equations.

2. Inopeki

Ok, but can you give me an example so i can try?

3. agdgdgdgwngo

here's an easy one: 2x + y = 3 x + y = 1

4. Inopeki

2x + y = 3 + x + y = 1 Is this the right first step?

5. agdgdgdgwngo

you can do 3 different things to solve a linear system: 1. graph the equations, and find where they intersect. 2. substitution 3. elimination.

6. Inopeki

Im gonna do elimination then substitution

7. Inopeki

No wait

8. Inopeki

I cant do elimination on this one

9. Inopeki

2x + y = 3 + x + -y = 1-2y 3x=4-2y

10. Inopeki

That cant be right

11. agdgdgdgwngo

you can; in fact elimination would be the easy way out of this one

12. Inopeki

WAIT

13. Inopeki

Can i divide the equations?

14. agdgdgdgwngo

if you subtract equation 2 from equation 1: you get x = 2 x + y = 1 next step is to subtract the new equation 1 from equation 2

15. Inopeki

y=1?

16. agdgdgdgwngo

you can't really divide the equations

17. Inopeki

Ok, i see why now

18. Inopeki

Give me another one so i can try, i think i see the pattern

19. agdgdgdgwngo

2x + y = 5 x + y = 3

20. Inopeki

2x + y = 5 - x + y = 3 = x=2? The y's cancel out right?

21. Inopeki

Now i can substitute to get y

22. agdgdgdgwngo

right

23. Inopeki

2 + y = 3 y=1

24. Inopeki

I can cross check this with the other equation

25. Inopeki

4 + 1 = 5 2 + 1 = 3