Let a_1, a_2, a_3, \dots, a_8, a_9, a_{10} be an arithmetic sequence. If a_1 + a_3 + a_5 = 7 and a_2 + a_4 = 6, then find a_1.
a1 + a3 + a5 = 7
a1 + (a1 + 2d) +( a1 + 4d) = 7
3a1 + 6d = 7
a2 + a4 = 6
(a1 + d) + ( a1 + 3d ) = 6
2a1 + 4d = 6
3a1 + 6d = 7 mult through by 4
2a1 + 4d = 6 mult through by -6
12a1 + 24d = 28
-12a1 - 24d = -36 adding these we get
0 = - 8
No solution
+1839 
