Aparallelogram is symmetric with respect to either diagonal. true or false?

Ineed with number 17 i don’t get it at alll

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

Richard save $32 in march he saved $48 in april and $38 in may then richard spent $113 on a keyboard how much money does richard have left