math, really need some feedback on this asap.
posted by SAP on .
7r4s=7 (7)
4r+7s=61 (4)
49r  28s = 49
16r + 28s = 244

65r = 195
195/65 = 3 (simplified) (3, is the first number of the ordered pair.)
Now this is the part that I get lost on. I know I am suppose to substitute 3 into one of the equations above, but how do I determine which one. So if I substitute 3 into the 1st equation:
7(3)4s= 7
21  4s= 7

21 = 7 would my answer be 7/21
Substitute 3 into the 2nd equation:
4(3)+7s = 61
12 + 7s = 61

12 = 61 would my answer be 61/12
(3, is the first number of the ordered pair.)
(3,7/21) or (3,61/12) which ordered pair is correct?

After reworking the problem, I'm pretty confident this is the correct answer to the 2nd part of the problem. Can someone confirm my work....
Now this is the part that I get lost on. I know I am suppose to substitute 3 into one of the equations above, but how do I determine which one. So if I substitute 3 into the 1st equation:
7(3)4s= 7
21  4s= 7

21 = 7 would my answer be 7/21