## anonymous one year ago solve the system by either elimination or substitution 3x-5y=21 2x+y=1 A.2,-3 B.2,3 C.-2,-1 D.-2,1 My guess is c

1. freckles

you could multiply the second equation by 5 and then add the equations together afterwards thus eliminating the y

2. freckles

what would the second equation look like after multiplying it by 5?

3. freckles

$2x+y=1 \\ 5(2x+y)=5(1) \\ \text{ use distributive property on the left } \\ 5(2x+y)=5$

4. freckles

remember that is a(b+c)=ab+ac this is distributive property

5. anonymous

i got 10x+5y=5

6. freckles

|dw:1439573529408:dw| ok add the equations now

7. freckles

|dw:1439573561932:dw|

8. freckles

can you evaluate the following: 3+10 -5+5 and 21+5

9. anonymous

for the first one i got 13x=26

10. freckles

|dw:1439573634678:dw|

11. freckles

and 26/13 equals?

12. anonymous

2

13. freckles

going back to either equation we started with we will now insert this x to find y I choose that second equation that was: 2x+y=1 2(2)+y=1 4+y=1 solve for y

14. anonymous

-3

15. freckles

|dw:1439573810726:dw|

16. freckles

yep and as you see it doesn't matter which equation you used to find the other number

17. anonymous

Thank you very much! can you help me with one more

18. freckles

sure i might be able to post a new question just in case