document.write( "Question 641565: The width of a rectangle is 8m less them the length. The area is 308^2m. Solve for width and the length.
\n" );
document.write( "Please help
\n" );
document.write( "Thank you \n" );
document.write( "
Algebra.Com's Answer #403721 by josh_jordan(263)![]() ![]() You can put this solution on YOUR website! To solve, let's change the first two sentences into equations. The first sentence says that the width of a rectangle is 8m less than the length. In other words,\r \n" ); document.write( "\n" ); document.write( "W = L - 8\r \n" ); document.write( "\n" ); document.write( "The second sentence says that the area is \n" ); document.write( "\n" ); document.write( "L x W = 308\r \n" ); document.write( "\n" ); document.write( "Now, substitute L - 8 for the W in the second equation, and we will find our length:\r \n" ); document.write( "\n" ); document.write( "L x (L - 8) = 308\r \n" ); document.write( "\n" ); document.write( "Using the distributive property of multiplication, multiply L by (L - 8), which will give us:\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If we subtract 308 from both sides of the equal sign, we will have a quadratic equation:\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We can now solve for L by factoring, completing the square, or by using the quadratic formula. Factoring is the easiest, so let's see if there are two numbers that when multiplied give us -308, and when added, give us -8:\r \n" ); document.write( "\n" ); document.write( "1 x -308 = -308; 1 + -308 = -307 this won't work \n" ); document.write( "-1 x 308 = -308; -1 + 308 = 307 this won't work\r \n" ); document.write( "\n" ); document.write( "Let's try some bigger numbers. How about 14 and 22?\r \n" ); document.write( "\n" ); document.write( "-14 x 22 = -308; -14 + 22 = 8 this won't work \n" ); document.write( "14 x -22 = -308; 14 + -22 = -8 this works!\r \n" ); document.write( "\n" ); document.write( "We see that 14 and -22 work, so:\r \n" ); document.write( "\n" ); document.write( "(L + 14)(L - 22) = -308, so\r \n" ); document.write( "\n" ); document.write( "L = -14 and L = 22\r \n" ); document.write( "\n" ); document.write( "Now, the length of a rectangle can never be a negative number, so -14 cannot be our length. So, our length must be 22 meters\r \n" ); document.write( "\n" ); document.write( "We know from the first sentence in our problem, that the width is 8m less than the length. Since the length is 22, our width will be 8 less than that:\r \n" ); document.write( "\n" ); document.write( "22 - 8 = 14\r \n" ); document.write( "\n" ); document.write( "So, our width is 14m\r \n" ); document.write( "\n" ); document.write( "FINAL ANSWER: Length = 22m and Width = 14m \n" ); document.write( " |