1.2 ≤ a ≤ 1.6

5.6 ≤ b ≤ 6

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b ≤ 6  1/b ≥ 1/6

b ≥ 5.6  1/b ≤ 1/5.6

1/6 ≤ 1/b ≤ 1/5.6

1.2 * 1/6 ≤ a* 1/b ≤ 1.6/5.6

1.6/5.6 = 16/10 : 56/10 = 16/10 * 10/56 = 2/7

0.2 ≤ a/b ≤ 2/7

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b ≤ 6  -b ≥ -6

b ≥ 5.6  -b ≤ -5.6

-6 ≤ -b ≤ -5.6

-12 ≤ -2b ≤ -11.2

1.2 - 12 ≤ a - 2b ≤ 1.6 - 11.2

-10.8 ≤ a - 2b ≤ -9.6