Question

Factor this expression completely and then place the factors in the proper location on the grid. Note:

Place factors alphabetically in the grid! mn - 4 m - 5 n + 20

Answer 1

First we are going to group the terms that contains the common factor
`m` in one parenthesis, and the other ones in another parenthesis:

`mn-4m-5n+20`

`(mn-4m)-(5n+20)`
Notice that our the terms in our first parenthesis have a common factor
`m`, and the terms in our second one have the common factor
`5`. Lets factor those out:

`m(n-4)-5(n-4)`
Now we have a common factor
`(n-4)` in both terms, so we can factor those out as well:

`(n-4)(m-5)`

We can conclude that the completely factored expression ordered alphabetically is
`(m-5)(n-4)`.