Question

(5 + ) =  +  + 81 ( – 3) ( + 3) = а2 –  вставить пропущенные числа.

Answer 1

(5+90)=3+6+81
а другое не знаю

Answer 2

It seems like there might be some missing or unclear information in your equations. You have placeholders like "" and "а2" which don't have defined values. If you could provide the correct or complete equations, I'd be happy to help you solve them or fill in the missing numbers.