Tammy completed the following steps to simplify the expression
-5x²y - 3xy² - 2(4y + 2) - 2.5x²y.


-5x²y - 3xy² - 2(4y) + 2(2) - 2.5x²y

-5x²y - 3xy² - 8y + 4 - 2.5x²y

(-5x²y - 3xy² - 2.5x²y) - 8y + 4

(-5 - 3 - 2.5)x²y - 8y + 4

-10.5x²y - 8y + 4


Explain why Tammy's solution is incorrect. Then show how to correctly simplify the expression.