Question 165029
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Remember: {{{A[R]=LW}}}, EQN 1
but, {{{L=8+W}}}, susbt. in EQN 1
{{{A=(8+W)(W)}}}
{{{105=W^2+8W}}}
{{{W^2+8W-105=0}}}, perfect square 
{{{(W+15)(W-7)=0}}}
2 values ----{{{system(W=-15cm,highlight(W=7cm))}}}
Use {{{W=7cm}}}
Then, {{{L=8+7=15cm}}}
Check via EQn 1,
{{{105=15*7}}}
{{{105cm^2=105cm^2}}}
Thank you,
Jojo</pre>