# math

posted by on .

Simplify and evaluate using distributive property of multiplcation

3x-4(2x-5)

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

• math - ,

• math - ,

3x8x+20

• math - ,

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

• math - ,

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

3x-4(2x-5)

3x-(4X2x-4X5)

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

• math - ,

Two minuses make a plus.

• math - ,

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.

• math - ,

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

• to tyqwanza - ,

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.

• math - ,

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.