SOLUTION: Swimming Space. The length of a rectangular swimming pool is 2x-1 meters, and the width is x+2 meters. Write a polynomial A(x) that represents the area. Find A(5). Here is what

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Swimming Space. The length of a rectangular swimming pool is 2x-1 meters, and the width is x+2 meters. Write a polynomial A(x) that represents the area. Find A(5). Here is what      Log On


   

Question 205246: Swimming Space. The length of a rectangular swimming pool is 2x-1 meters, and the width is x+2 meters. Write a polynomial A(x) that represents the area. Find A(5).
Here is what I tried - (2x-1)(x+2) = A 3x-2 = A 3(5) - 2= A A = 13 meters
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
A(x) = (2x-1)(x+2) is correct! However (2x-1)(x+2) is NOT equal to 3x-2!!.

To multiply (2x-1)(x+2) you must use a method called FOIL (or something equivalent to it). The "F" stands for first:
2x%2Ax+=+2x%5E2
The "O" stands for outside:
2x+%2A+2+=+4x
The "I" stands for inside:
-1+%2A+x+=+-x
The "L" stands for last:
-1+%2A+2+=+-2

All together we get:

Now we can find A(5):