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## Algebra (all content)

### Course: Algebra (all content)ย >ย Unit 10

Lesson 5: Multiplying monomials by polynomials

# Multiplying monomials by polynomials

Sal multiplies -4x² by (3x² + 25x - 7). Created by Sal Khan and Monterey Institute for Technology and Education.

## Want to join the conversation?

• We add the exponents when we have the same base, what about if we have a different base?
• If you have a different base then you can't do that. It has to be the same base.
• When you multiply -y(x) do you get -xy or -yx
• Usually they are put in alphabetical order, so -xy is preferred, but as said they are equivalent.
• but doesnt the rule sau you do the brackets first BEDMAS
• He is! and the only way you can take away the brackets, (the P in PEMDAS (you spelled it wrong))
is multiplying out the terms in the brackets by the outside number, but the thing is, the brackets are for that! FOR EXAMPLE!

4x(3x + 45 - 4y)

the parentheses mean to multiply everything inside by the outside number so to clear up confusion...

6(8x - 9)

is the same as...

6 times 8x - 9

hope this helped! :D
• This probably isn't related to Distributive property or BEDMAS but can't I use FOIL for this? I'm confused :(
• FOIL is used when you are multiplying 2 binomials. In the video, the problems involve multiplying a monomial with a polynomial, which just uses the distributive property.
• Can anyone please tell me on how to multiply literals which have different powers?
• I don't know if this is the right place to ask, but what is monomial and polynomials? I looked it up but the definitions and examples are not very precise. Please help!
• Quick question: how in the world are you supposed to multiply 4xsquared with another number?
• Is there an example of problem the is written like 3(-5x^7)x^2
• nah i dont think so man
• How did he get the +'s in between the ( ) inthe first one he did, which is the one below the problem...