<PRE><B>Question 340986</B>
Find two numbers who sum is 30 so that 5 times the larger number decreased by three times the smaller number is 54
--
Let S=small number
Let L=large number
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given
S+L=30
5L-3S=54
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S=30-L  solve for one of the variables
5L-3(30-L)=54  subtitute into the other equation
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5L-90+3L=54
8L-90=54
8L=144
L=144/8=18
==
{{{highlight_red(L=18)}}} and {{{highlight_red(S=30-L=12)}}}
==
validate
5L-3S=54
5(18)-3(12)=90-36=54 check</PRE>