Answer:
3a+6b = 45
Multiply by 2
6a +12b = 90.....(1)
2a- 2b = -12
Multiply by 3
6a - 6b = -36 .....(2)
(1)-(2)
18b = 126
b= 7
3a + 6(7) = 45
3a +42 = 45
3a = 3
a= 1
(a,b) = ( 1,7)
