Answer:
Step-by-step explanation:
A) x/840=1/21
x=(1/21)*840=840/21=40
x=40
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B) 14/x=16/20
simplify 16/20 into 4/5
14/x=4/5
x=14/(4/5)=(14/1)(5/4)=70/4
simplify
x=35/2
