document.write( "Question 511789: The Nelson family has discovered that the cost C of their family vacation is a constant k times the length d, in days, of the vacation added to the cost t of transportation to get to and from their vacation spot, as shown by the function C(d) = kd + t. The Nelson family had to shorten their planned vacation by 3 days. How much less did the shortened vacation cost than the original planned vacation? \n" ); document.write( "

Algebra.Com's Answer #342409 by josmiceli(19441) $\"\"$ $\"About$

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Their original vacation was
\n" ); document.write( " $\"+C%28d%29+=+k%2Ad+%2B+t+\"$
\n" ); document.write( "Their shortened vacation was
\n" ); document.write( " $\"+C%28d-3%29+=+k%2A%28d-3%29+%2B+t+\"$
\n" ); document.write( "The difference in cost is
\n" ); document.write( " $\"+C%28d%29+-+C%28d-3%29+=+k%2Ad+%2B+t+-+k%2A%28d-3%29+-+t+\"$
\n" ); document.write( " $\"+C%28d%29+-+C%28d-3%29+=+k%2Ad+-+k%2Ad+%2B+3k+\"$
\n" ); document.write( " $\"+C%28d%29+-+C%28d-3%29+=+3k+\"$
\n" ); document.write( "check:
\n" ); document.write( "Suppose
\n" ); document.write( " $\"+k+=+11+\"$
\n" ); document.write( " $\"+d+=+9+\"$
\n" ); document.write( " $\"+t+=+17+\"$
\n" ); document.write( " $\"+C%289%29+=+11%2A9+%2B+17+\"$
\n" ); document.write( " $\"+C%289%29+=+116+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+C%289-3%29+=+11%2A%289-3%29+%2B+17+\"$
\n" ); document.write( " $\"+C%286%29+=+66+%2B+17+\"$
\n" ); document.write( " $\"+C%286%29+=+83+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+C%289%29+-+C%286%29+=+116+-+83+\"$
\n" ); document.write( " $\"+C%289%29+-+C%286%29+=+33+\"$
\n" ); document.write( " $\"+k+=+11+\"$
\n" ); document.write( " $\"+3k+=+33+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );