(4,5у+9)-(6,2-3,1у)=7,2у+2,8

To solve the given expression, let's first simplify each polynomial separately:

\( (4,5у + 9) = 4,5у + 9 \) \( (6,2 - 3,1у) = 6,2 - 3,1у \)

Now, let's subtract the second polynomial from the first one:

\( (4,5у + 9) - (6,2 - 3,1у) \)

This is equivalent to:

\( 4,5у + 9 - 6,2 + 3,1у \) \( 4,5у + 3,1у + 9 - 6,2 \) \( 7,6у + 2,8 \)

Therefore, the simplified expression is \( 7,6у + 2,8 \).