Question 335464
You are going to use substitution to answer this problem.
First make clear what will represent what. You write a let statement for this.
 Step 1:Let a= adults and Let c = children
we know that there are 737 people total so we write the equation
step 2:     a + c = 737

we know that there are 289 more adults than children. So adults a minus 289 = children c. so you substitute that into your equation a + (a-289) = 737

step 3: a+a = 2a and  you can't add letters and number so it become 2a-289 =737

step 4:    2a -289 = 737 add 289 to both sides to get the a on a side by its self         2a = 1026

step 5: divide both sides by 2 to get the a alone
         2a /2 =  a   and  1026/2 = 513
so a = 513

Step 6: plug it in to the orginal a + c = 737
                                513 + c = 737
subtract 513 from both sides    c = 224

now you have the value of both a and c you can plug them in and check
a + c = 737
513 + 224 =737

so there were 224 children and 513 adults.