document.write( "Question 1094142: A machine is now worth $155,800 and will be depreciated linearly over a 10 year period, at which time it will be worth $40,300 as scrap.
\n" ); document.write( "(a) Find the rule of depreciation function f.
\n" ); document.write( "(b) What is the domain of f?
\n" ); document.write( "(c) What will the machine be worth in 7 years? \n" ); document.write( "

Algebra.Com's Answer #708740 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+t+\"$ = time in years, starting now at $\"+t=0+\"$
\n" ); document.write( "Plot $\"+t+\"$ on the horizontal
\n" ); document.write( "Plot $\"+f+\"$ on the vertical
\n" ); document.write( "You are given 2 points on a line,
\n" ); document.write( "( 0, 155800 )
\n" ); document.write( "( 10, 40300 )
\n" ); document.write( "-------------------------------
\n" ); document.write( "(a)
\n" ); document.write( "Use the general point-slope formula
\n" ); document.write( " $\"+%28+f+-+40300+%29+%2F+%28+t+-+10+%29+=+%28+155800+-+40300+%29+%2F+%28+0+-+10+%29+\"$
\n" ); document.write( " $\"+%28+f+-+40300+%29+%2F+%28+t+-+10+%29+=+115500+%2F+%28-10+%29+\"$
\n" ); document.write( " $\"+%28+f+-+40300+%29+%2F+%28+t+-+10+%29+=+-11550+\"$
\n" ); document.write( " $\"+f+-+40300+=+-11550t+%2B+115500+\"$
\n" ); document.write( " $\"+f+=+-11550t+%2B+155800+\"$
\n" ); document.write( "------------------------------------
\n" ); document.write( "check:
\n" ); document.write( "does it go through ( 10, 40300 ) ?
\n" ); document.write( " $\"+40300+=+-11550%2A10+%2B+155800+\"$
\n" ); document.write( " $\"+40300+=+-115500+%2B+155800+\"$
\n" ); document.write( " $\"+40300+=+40300+\"$
\n" ); document.write( "OK
\n" ); document.write( "--------------
\n" ); document.write( "(b)
\n" ); document.write( "The domain is from ( 0, 155800 ) to ( t, 0 )
\n" ); document.write( " $\"+0+=+-11550t+%2B+155800+\"$
\n" ); document.write( " $\"+11550t+=+155800+\"$
\n" ); document.write( " $\"+t+=+13.49+\"$ yrs
\n" ); document.write( "The domain is from 0 to 13.49
\n" ); document.write( "-------------------------------
\n" ); document.write( "(c)
\n" ); document.write( "Find ( 7, f )
\n" ); document.write( " $\"+f+=+-11550%2A7+%2B+155800+\"$
\n" ); document.write( " $\"+f+=+-80850+%2B+155800+\"$
\n" ); document.write( " $\"+f+=+74950+\"$
\n" ); document.write( "It is worth $74,950 in 7 yrs
\n" ); document.write( "------------------------------
\n" ); document.write( "check the math\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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