Simplify and evaluate using distributive property of multiplcation

Question

3x-4(2x-5)

I've tried many ways and can't come up with the same answer as the teacher. help please?

Answer 1

What answer does your teacher have?

Answer 2

3x8x+20

Answer 3

No. 3x-8x+20=-5x+20 or 5(4-x)

Answer 4

ok..i guess that is where i'm confused

3x-4(2x-5)

3x-(4X2x-4X5)

3x-(8x-20) (this was my answer)

I still not sure how the teacher and you came up with +20 instead of -20?

Answer 5

Two minuses make a plus.

Answer 6

3x-(4X2x-4X5)
The - outside the parentheses changes the sign of everything inside the parentheses. Therefore, the 4*3x becomes -(8x) or -8x and the -4*5 becomes -(-20) or + 20.

Answer 7

use the number line.is 458 closer to 450 or to 460

Answer 8

If you have a separate question to post, go to the top of the page and click on post a new question. Piggy backing onto another question rarely results in an answer for the piggy backer.

Answer 9

Than you all. Dr. Bob222 that was exactly what I was missing, I could not see where the 2 minuses where together since our teacher explained it differently. This was very clear.
Thank you.