To expand the expression (-y)^4, we can multiply -y by itself four times:
(-y)^4 = (-y) * (-y) * (-y) * (-y)
Now, let's simplify:
(-y) * (-y) = y^2 (Multiplying two negatives gives a positive)
y^2 * (-y) = -y^3 (Multiplying a positive and a negative gives a negative)
-y^3 * (-y) = y^4 (Multiplying two negatives gives a positive)
So, the expanded form of (-y)^4 is: (-y) * (-y) * (-y) * (-y) = y^4
The simplified answer is: y^4