Posted by soliman on Tuesday, September 15, 2009 at 3:02pm.
Simplify and evaluate using distributive property of multiplcation
3x4(2x5)
I've tried many ways and can't come up with the same answer as the teacher. help please?

math  Ms. Sue, Tuesday, September 15, 2009 at 3:18pm
What answer does your teacher have?

math  soliman, Tuesday, September 15, 2009 at 3:20pm
3x8x+20

math  bobpursley, Tuesday, September 15, 2009 at 3:26pm
No. 3x8x+20=5x+20 or 5(4x)

math  soliman, Tuesday, September 15, 2009 at 3:30pm
ok..i guess that is where i'm confused
3x4(2x5)
3x(4X2x4X5)
3x(8x20) (this was my answer)
I still not sure how the teacher and you came up with +20 instead of 20?

math  Ms. Sue, Tuesday, September 15, 2009 at 3:36pm
Two minuses make a plus.

math  DrBob222, Tuesday, September 15, 2009 at 3:48pm
3x(4X2x4X5)
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  tyqwanza, Tuesday, September 15, 2009 at 4:38pm
use the number line.is 458 closer to 450 or to 460

to tyqwanza  DrBob222, Tuesday, September 15, 2009 at 4:44pm
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  Anonymous, Tuesday, September 15, 2009 at 4:54pm
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.
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