document.write( "Question 572708: The length of a rectangle is 5 inches longer than the width. The area of the rectangle is 50 inches squared. Find the length and the width of the rectangle. \n" ); document.write( "
Algebra.Com's Answer #368615 by mathsmiles(68) You can put this solution on YOUR website! First thing we want to do is write down what we know:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Area of a rectangle: \n" ); document.write( "A = L x W \n" ); document.write( "L = 5 + W (length is 5 inches longer than the width) \n" ); document.write( "A = 50 (Area is 50 inches squared)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Putting this all together: \n" ); document.write( "L x W = 50 \n" ); document.write( "Substituting for L with the above equation: \n" ); document.write( "(5+W) x W = 50 \n" ); document.write( "Multiplying out the paren \n" ); document.write( "5W + W^2 = 50 \n" ); document.write( "Subtract 50 from both sides and rearrange the terms a little: \n" ); document.write( "W^2 + 5W - 50 = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now solve: \n" ); document.write( "(W _ _) (W _ _) = 0 (we need to figure out the operand and the term for each) \n" ); document.write( "The negative whole number indicates these have different signs \n" ); document.write( "(W - _) (W + _) = 0 \n" ); document.write( "We need to find two factors of 50 whose difference (subtract them) gives 5. \n" ); document.write( "50 = 25 x 2 Nope \n" ); document.write( "50 = 5 x 10 Yup!\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since the 5W term is positive, we need to put the 10 in the positive factor and 5 in the negative factor so ... \n" ); document.write( "(W - 5)(W + 10) = 0 \n" ); document.write( "W -5 = 0 \n" ); document.write( "W = 5 \n" ); document.write( "W + 10 = 0 \n" ); document.write( "W = -10\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since we're talking about the area of a rectangle, we have to assume it has positive sides or we've just entered another dimension. :-) So, \n" ); document.write( "W = 5 inches \n" ); document.write( "L = 5 + 5 (5 inches longer than the width) \n" ); document.write( "L = 10 inches\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Checking: \n" ); document.write( "A = L x W \n" ); document.write( "A = 5 x 10 \n" ); document.write( "50 = 50 Correct! \n" ); document.write( " |