$149,000 estate is to be divided between two charities so that one charity receives $18,000 less than the other. how much will each charity receive?

For this case, the first thing we must do is define variables.
 We have then:
 x: amount of money for charity 1.
 y: amount of money for charity 2.
 We now write the system of equations that models the problem:
 
 We solve the system.
 Using substitution we have:
 
 Clearing x:
 
 Then, the value of the second charity is:
 
 
 charity 1 = $ 83500
 charity 2 = 65500 $