Question

5n - 6mn; 3n - 6mn + 2n; 15.5 + 5mn - 11mn; y + 21y; 6m; m; a.7x; e.-6; a.-1; l.2x; d.4

Explanation:

To solve the expression \( 15.5 + 5mn - 11mn \), we combine like terms (the terms with \( mn \)):

Step 1: Identify like terms

The terms with \( mn \) are \( 5mn \) and \( -11mn \). The term \( 15.5 \) is a constant and does not have a variable, so it remains as is.

Step 2: Combine like terms

To combine \( 5mn \) and \( -11mn \), we subtract their coefficients:
\[
5mn - 11mn = (5 - 11)mn = -6mn
\]

Step 3: Write the simplified expression

Now we substitute the combined like terms back into the original expression:
\[
15.5 + (5mn - 11mn) = 15.5 - 6mn
\]

Answer:

\( 15.5 - 6mn \)