Show/hide field conditionally in sharepoint form based on multiple conditions

Hiya i would like to show / hide a question within my lists form based on multiple conditions. So i want this question to show only when 

1. Question 1 has answer X

2. Question 2 has answer Y.

I've tried like this i get "Enter a valid condition". 

=IF(AND([$category1] == 'X', [$category2] =='Y'), 'true', 'false')