Question 751548
5s + 9t = 6
4s - 3t = 15

Multiply 2nd equation by 3 --> 12s - 9t = 45

Now add to 1st
 5s + 9t = 6
+(12s - 9t = 45)
-----------------
17s = 51

s = 3

Plug s = 3 into original 2nd equation:
4(3) - 3t = 15 --> 12 - 3t = 15 
-3t = 3

t = -1

FINAL ANSWER: s = 3, t = -1