Question 966585
dimensions w and L.
Formula for perimeter, p:   p=2w+2L


Transcribe your description.
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p=2w+2L  and you are given p=204.
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L=-6+2w


{{{system(L=2w-6,2w+2L=204)}}}


More than one way to solve the system for w and L, but in this case,
(1) Simplify the perimeter equation;
(2) Substitute for L;
(3) Solve for w;
(3) Use result for w to evaluate L.