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题库 / OG2021-PS-110
For all real numbers a, b, c, d, e, and f, the operation ㊀ is defined by the equation (a, b, c) ㊀ (d, e, f) = ad + be + cf. What is the value of (1, -2, 3 ) ㊀ (1, -~$1 \over 2$~, ~$1 \over 3$~)?
-1
~$5 \over 6$~
1
~$5 \over 2$~
3
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