SOLUTION: when do you cross multiply fractions and when do you just multiply the numerators and denominators

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Question 40102: when do you cross multiply fractions and when do you just multiply the numerators and denominators
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
You only "cross-multiply" when two fractions are set equal into a proportion...
Thus if you have A/B = C/D, you can cross-multiply and get
AD = BC
If the fractions are on the same side of an equal sign, you merely multiply numerators and denominators...