start by thinking of the number 22 as divided into 22 individual items and the variables x1, x2, and x3 as three categories into which these items are placed. since each xi is a positive correct: your answer is correct. integer, start by placing one item in each category and distribute the remaining items among the categories. the number of solutions to the equation that satisfy the given condition is the number of ways to place all the items into the categories. thus, the answer is 20 incorrect: your answer is incorrect. .