document.write( "Question 169630: The area of a rectangle is 15m^2 + 11m - 12. Find the length if the width is 5m-3 \n" ); document.write( "
Algebra.Com's Answer #125053 by gonzo(654)\"\" \"About 
You can put this solution on YOUR website!
area of a rectangle equals length * width.
\n" ); document.write( "let A = area
\n" ); document.write( "let L = length
\n" ); document.write( "let W = width
\n" ); document.write( "A = L*W
\n" ); document.write( "-----
\n" ); document.write( "you are given the area and the width.
\n" ); document.write( "you want to find the length
\n" ); document.write( "-----
\n" ); document.write( "A = L*W
\n" ); document.write( "divide both sides of equation by W:
\n" ); document.write( "A/W = L
\n" ); document.write( "which is the same as:
\n" ); document.write( "L = A/W
\n" ); document.write( "-----
\n" ); document.write( "A = 15m^2 + 11m - 12
\n" ); document.write( "W = 5m-3
\n" ); document.write( "-----
\n" ); document.write( "substitute for A and W:
\n" ); document.write( "L = (15m^2 + 11m - 12) / (5m-3)
\n" ); document.write( "-----
\n" ); document.write( "this is a straight long division problem:
\n" ); document.write( "first you figure how many times 5m will divide into 15m^2.
\n" ); document.write( "answer is:
\n" ); document.write( "3m ********* this is the first part of your answer.
\n" ); document.write( "then you multiply (5m-3) * 3m
\n" ); document.write( "answer is:
\n" ); document.write( "(15m^2 - 9m)
\n" ); document.write( "then you subtract (15m^2 - 9m) from (15m^2 + 11m - 12)
\n" ); document.write( "answer is:
\n" ); document.write( "(15m^2 + 11m - 12) - (15m^2 - 9m) =
\n" ); document.write( "15m^2 + 11m - 12 - 15m^2 + 9m =
\n" ); document.write( "(20m - 12)
\n" ); document.write( "-----
\n" ); document.write( "next you figure out how many times 5m goes into 20m.
\n" ); document.write( "answer is:
\n" ); document.write( "4 ********* this is the second part of your answer
\n" ); document.write( "then you multiply (5m-3) * 4
\n" ); document.write( "answer is:
\n" ); document.write( "(20m - 12)
\n" ); document.write( "then you subtract (20m-12) from (20m - 12)
\n" ); document.write( "answer is:
\n" ); document.write( "20m - 12 - (20m - 12) =
\n" ); document.write( "20m - 12 - 20m + 12 =
\n" ); document.write( "0
\n" ); document.write( "-----
\n" ); document.write( "your answer for (15m^2 + 11m - 12) / (5m-3) is (3m + 4)
\n" ); document.write( "(3m+4) is the length.
\n" ); document.write( "-----
\n" ); document.write( "to prove your answer is correct, go back to the original equation of:
\n" ); document.write( "A = L*W
\n" ); document.write( "substitute for A, L, and W:
\n" ); document.write( "15m^2 + 11m - 12 = (3m+4)*(5m-3)
\n" ); document.write( "(3m+4)*(5m-3) = 15m^2 - 9m + 20m - 12 =
\n" ); document.write( "15m^2 + 11m - 12.
\n" ); document.write( "this is the same as the area you started with so the equation is true proving that the value of (3m+4) for the length is good.
\n" ); document.write( "-----
\n" ); document.write( "your answer is:
\n" ); document.write( "length = (3m+4)
\n" ); document.write( "-----
\n" ); document.write( "
\n" ); document.write( "
\n" );