document.write( "Question 400415: The length of a rectangle is 8 centimeters less than 3 times with width.
\n" ); document.write( "a write a polynomial that represents the area of the rectangle
\n" ); document.write( "b find the area of the rectangle when the width is 10 centimeters. \n" ); document.write( "

Algebra.Com's Answer #283528 by jsmallt9(3758) $\"\"$ $\"About$

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Let w = width. Then, since the length is 8 less than 3 times the width,:
\n" ); document.write( "l = 3w - 8
\n" ); document.write( "Note how the English \"8 less than 3 times the width\" is in the opposite order to the expression 3w - 8. This is often the case with subtraction. You have to be careful with these. Just ask your self: \"How do I figure out 8 less than a number?\" With some thought you should be able to figure out that you subtract 8 from the number, n-8, not subtract the number from 8, 8-n.

\n" ); document.write( "Since area of a rectangle is length times width, A = lw, we can use:
\n" ); document.write( "A = (3w-8)(w)
\n" ); document.write( "for the area of this rectangle. Multiplying out the right side we get:
\n" ); document.write( " $\"A+=+3w%5E2+-+8w\"$
\n" ); document.write( "This is the answer to part a.

\n" ); document.write( "To find the area when the width is 10, we just substitute a 10 for w:
\n" ); document.write( " $\"A+=+3%2810%29%5E2+-+8%2810%29\"$
\n" ); document.write( "which simplifies as follows:
\n" ); document.write( "A = 3(100) - 8(10)
\n" ); document.write( "A = 300 - 80
\n" ); document.write( "A = 220 square centimeters. \n" ); document.write( "

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