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How would combine 4x+5x?

How do I combine these? It's a question I need to answer today in math class but I do not get it

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Ye Hong K. | Experienced Singapore senior high school lecturerExperienced Singapore senior high school...
5.0 5.0 (1 lesson ratings) (1)
Hi Stacy,
You can think of x as the number of things (say apples):
If I have 4 apples and 5 apples, how many apples do I have? (9 apples)
Likewise, you have 4x and 5x, so you have 9x altogether.
similarly, if I have 9 apples and you take away 4 apples from me, how many apples do I have? (5)
likewise 9x - 4x = 5x.
Let's look at 2 items now.
If I have 4 apples and 5 oranges, there is no way you can add them up different they are different items.
So 4x + 5y = 4x + 5y.
Hope this help you have a better understanding of algebra.
Vivian L. | Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACHMicrosoft Word/Excel/Outlook, essay comp...
3.0 3.0 (1 lesson ratings) (1)
Hi Stacy;
4x is x+x+x+x
5x is x+x+x+x+x
9x is x+x+x+x+x+x+x+x+x