при a = 9 и b = 8:
3a + 4b = 3 * 9 + 4 * 8 = 27 + 32 = 59
12a − 7b = 12 * 9 − 7 * 8 = 108 − 56 = 52

при a = 100 и b = 10:
3a + 4b = 3 * 100 + 4 * 10 = 300 + 40 = 340
12a − 7b = 12 * 100 − 7 * 10 = 1200 − 70 = 1130

при a = 7 и b = 3:
3a + 4b = 3 * 7 + 4 * 3 = 21 + 12 = 33
12a − 7b = 12 * 7 − 7 * 3 = 84 − 21 = 63

при a = 1 и b = 0:
3a + 4b = 3 * 1 + 4 * 0 = 3 + 0 = 3
12a − 7b = 12 * 1 − 7 * 0 = 12 − 0 = 12

при a = 5 и b = 5:
3a + 4b = 3 * 5 + 4 * 5 = 15 + 20 = 35
12a − 7b = 12 * 5 − 7 * 5 = 60 − 35 = 25

Ответ:

a	9	100	7	1	5
b	8	10	3	0	5
3a + 4b	59	340	33	3	35
12a − 7b	52	1130	63	12	25