Question 1093588
formula F = C + 32
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Using that, never.
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F = (9/5)C + 32
F = 1.8C + 32
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C = 1.8C + 32
-0.8C = 32
C = -40
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-40C = -40F
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That's close to the freezing point of Hg, -39.6.
I forget if that's C or F, but I doesn't matter here.