document.write( "Question 586543: Find the length and width of the rectangle with the area of 35cm, whose length is x+4cm and width x+2cm
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Algebra.Com's Answer #373782 by tw23279(14) ![]() You can put this solution on YOUR website! At first, you have to recognize that 35cm is the area of a rectangle. \n" ); document.write( "Recall that the area of a rectangle = length x width. \n" ); document.write( "And we have 35cm = (x+4)(x+2) by substituting area with 35cm (it's given) and length with (x+4)cm and width by (x+2)cm (which are also given). \n" ); document.write( "So, foil out (x+4)(x+2) -> x^2 + 2x + 4x + 8 -> x^2 + 6x + 8 \n" ); document.write( "So we know that x^2+6x+8 = 35 \n" ); document.write( "Move everything to one side so you can solve for x using quadratics. \n" ); document.write( "x^2 + 6x - 27 = 0 \n" ); document.write( "Think of two numbers that will add up to 6 and multiply to -27. \n" ); document.write( "So we get that.. \n" ); document.write( "(x+9)(x-3) = 0 \n" ); document.write( "x = -9 OR x = 3 because remember that if x times y = 0, then x OR y = 0 \n" ); document.write( "Since we are looking for the MEASURE of something and that can't be negative. \n" ); document.write( "It will be that x = 3 \n" ); document.write( "Length = x+4 = 7 cm \n" ); document.write( "Width = x+2 = 5 cm \n" ); document.write( " |