PLEASE HELP Simplify an expression

(X2y4z)5/ (Xy)2

Flashback to semester a. are triangles pqr and stu congruent? what is the congruency that proves they are congruent? what is the perimeter of triangle pqr? show your work.

Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard deviation 0.070 g. a vending machine will only accept coins weighing between 5.48 g and 5.82 g. what percentage of legal quarters will be rejected? round your answer to two decimal places.

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?