Answer:
None.
Step-by-step explanation:
6x-20=32
6(8)-20=48-20=28, not 32
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16-x=12
16-8=8, not 12
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20-0.4x=13.8
20-0.4(8)=20-3.2=16.8, not 13.8
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1x+12=30
x+12=30
8+12=20, not 30
