Fixed typo: errant comma

Author: paulvojta

OpenProblemLibrary/Michigan/Chap4Sec7/Q29.pg

@@ -50,7 +50,7 @@ TEXT(beginproblem());
 Context()->texStrings;
 BEGIN_TEXT
 
-If \( x \), and \( y \) are both positive, evaluate
+If \( x \) and \( y \) are both positive, evaluate
 $PAR
 \(\displaystyle \lim_{p\rightarrow 0}\frac{\ln($a\, x^p + $b\, y^p)}{p} =\)
 \{ ans_rule(35) \}