How do you combine like terms for #-7mn-2mn^2-2mn + 8#?

1 Answer
Dec 24, 2014

In this expression only the first #-7mn# and the third #-2mn# are like terms. They both have the same literary part #mn# to the same powers and they can be added together.
The second term #-2mn^2# has #mn# as well BUT #n# is raised to the power #2#!!!

Imagine that like terms are objects. You can add or subtract together the same objects (for example 5 apples+2 apples= 7 apples) while you CANNOT do it with different objects (for example: 3 apples + 5 chairs=???)

In your case you can now write:

#-7mn-2mn^2-2mn+8# as:
#(-7mn-2mn)-2mn^2+8#
#-9mn-2mn^2+8#