document.write( "Question 288390: what is the length and width of a rectangle if the perimeter is 24m and the area is 35m2? \n" ); document.write( "
Algebra.Com's Answer #209037 by jaydducote(11)\"\" \"About 
You can put this solution on YOUR website!
Area=length times width, or A=LW
\n" ); document.write( "Perimeter=2W+2L
\n" ); document.write( "We know the perimeter is 24m, so 24=2W+2L
\n" ); document.write( "We know the area is 35 square meters, so 35=LW
\n" ); document.write( "Now you need to do substitution to solve. You have to solve for either L or W in terms of the other variable. I would solve the first one for W:
\n" ); document.write( "24=2W+2L
\n" ); document.write( "subtract 2L from both sides
\n" ); document.write( "24-2L=2W
\n" ); document.write( "now divide both sides by 2
\n" ); document.write( "12-L=W
\n" ); document.write( "so we know that W=12-L. Substitute that into the other equation:
\n" ); document.write( "35=LW
\n" ); document.write( "35=L(12-L)
\n" ); document.write( "distribute the L
\n" ); document.write( "35=12L-L^2
\n" ); document.write( "This now looks tricky, there is a square term, so we will need to factor
\n" ); document.write( "Move everything to the left side
\n" ); document.write( "L^2-12L+35=0
\n" ); document.write( "Now, think about which two numbers add to twelve and multiply to get 35. Think of the factors of 35. Only 7 times 5 works, which happen to add to 12!
\n" ); document.write( "Since we have a -12L but a +35, and we know we are adding to get to 12, not subtracting, we should conclude that both the 7 and 5 must be negative. Factored, we get this:
\n" ); document.write( "(L-5)(L-7)=0
\n" ); document.write( "This means that our two \"zeros\" or solutions are the numbers that make this statement true. If L is 5 or 7, the entire value is 0, so those are our answers. W=5, L=7.
\n" ); document.write( "
\n" );