Midterm Exam 1 Tuesday, September 18, 2007 Name Purdue ...

1 + y 2 + y 3 = 19 with y i 0 for all i. There are 19+3 1 3 1 = 21 2 = 210 solutions to this equation (as discussed in Proposition 6.2). So the correct answer is B, namely, 210. Another possible method of solution is to de ne y 1 = x 1 1 and y 2 = x 2 1 1 and y 3 = x 3 2 1, so that x 1 +x 2 +x 3 = 25 becomes x 1 +(x 2 1)+(x 3 2) = 25 1 2, or ... ................
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