Baseball Wins

Date: 9/10/96 at 17:4:41
From: Anonymous
Subject: How Many Baseball Team Wins

A baseball team won 4 more games than it lost. The team played 
18 games.  How many games did it win?

my answer:
let the number of games won  = x+4
let the number of games lost = x

x+4=18
x=22 

This is the answer I get and as you can see it is wrong.
Please help me.

Date: 9/11/96 at 0:16:55
From: Doctor Mike
Subject: Re: How Many Baseball Team Wins

Dear Sorena,

You got started right by letting x be the number of games lost, but 
18 is the total number of games they played, including the games they 
won and also the ones they lost, so the equation is "number of games 
won plus number of games lost equals 18."  

In symbols that is (x+4) + x = 18.  You can take it from here.
  
I want to warn you not to repeat a mistake in what you wrote. The 
equation x+4 = 18 is not the right equation, but there is something 
else wrong. If you start with that equation and solve for x you should 
not get x = 22. Here's why. Always think of doing the same thing to 
both sides of the equation.  In this case you need to subtract 4 from 
each side, which leaves you with just x on the left side, and 18-4=14 
on the right side. Be sure to watch out for this as you solve for x 
with the new equation.
  
I hope this helps.   

-Doctor Mike,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/