<PRE><B>Question 241341</B>
Solve using the principle of zero products. thank you 
(21 - 0.8x)(5 - 0.4x) = 0 
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Since the product is zero, at least one of those factors 
must be zero.
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If 21-0.8x = 0
then 0.8x = 21
and x = 26.25
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OR
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If 5-0.4x = 0
then 0.4x = 5
and x = 12.5
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Cheers,
Stan H.</PRE>