To simplify the expression, we need to combine like terms:
-у × 2у - 1 + 3у^2 - у × 5 + 7у^2 × у + 3= -2у^2 - 1 + 3у^2 - 5у + 7у^3 + 3= 7у^3 + у^2 - 5у + 2
Therefore, the simplified expression is 7у^3 + у^2 - 5у + 2.
To simplify the expression, we need to combine like terms:
-у × 2у - 1 + 3у^2 - у × 5 + 7у^2 × у + 3
= -2у^2 - 1 + 3у^2 - 5у + 7у^3 + 3
= 7у^3 + у^2 - 5у + 2
Therefore, the simplified expression is 7у^3 + у^2 - 5у + 2.