Add.

To add the two expressions \((-4y + 6)\) and \((-8y + 4)\), you simply combine like terms. Here are the steps:

1. Write down the expressions: \[ (-4y + 6) + (-8y + 4) \]

2. Remove the parentheses: \[ -4y + 6 - 8y + 4 \]

3. Combine the like terms for \(y\): \[ -4y - 8y = -12y \]

4. Combine the constant terms: \[ 6 + 4 = 10 \]

5. Combine the results: \[ -12y + 10 \]

So, the final result is: \[ -12y + 10 \]