To simplify this expression, we distribute the negative sign outside the parentheses and combine like terms:

7 - (3 + 1) - 0.1y = -0.2y

This simplifies to:

7 - 4 - 0.1y = -0.2y

3 - 0.1y = -0.2y

Now, we can subtract 0.1y from both sides of the equation to isolate the variable y:

3 = -0.1y - 0.2y

3 = -0.3y

Finally, we divide both sides by -0.3 to solve for y:

y = -10