# Math Question

flyUnity
Posers and Puzzles 14 May '06 23:27
1. 14 May '06 23:273 edits
I know this is not the place to ask math questions, but since Im doing an online math class, Its hard for me to ask a real person.

In my Math textbook, Im having a hard time understanding this problem, I know its something simple, I just cant figure out what. The fact that Im dum at math isnt helping any.

Simplify: -2(x-5)+ 4(2x + 2)

This is how the book says to simplify.
-2(x-5)+ 4(2x + 2) = -2*x + (-2)(-5) + 4*2x + 4/2
= -2x + 10 + 8x +8
= 6x + 18

This is how it seems to me it should go, which gives it a totaly different answer.
-2(x-5)+ 4(2x + 2) = -2*x -(-2)(-5) + 4*2x + 4/2
= -2x - 10 + 8x +8
= -2x + (-10) + 8x +8
= 6x + (-2) or = 6x - 2

So what am I doing wrong? Why are they changing the minus sign to a plus sign when they are caculating, for no reason at all?

* = mutiply
2. 14 May '06 23:38
Originally posted by flyUnity
This is how it seems to me it should go, which gives it a totaly different answer.
-2(x-5)+ 4(2x + 2) = -2*x -(-2)(-5) + 4*2x + 4/2
= -2x - 10 + 8x +8
= -2x + (-10) + 8x +8
= 6x + (-2) or = 6x - 2

So what am I doing wrong? Why are they changing the minus sign to a plus sign when they are caculating, for no reason at all?

* = mutiply
your problem is in the first distribution. The -2 needs to go to the x, which you did right, but also to the -5, and (-2)*(-5) is (+10).
3. 14 May '06 23:43
Originally posted by Coconut
your problem is in the first distribution. The -2 needs to go to the x, which you did right, but also to the -5, and (-2)*(-5) is (+10).
Ok, I got it now, I dont know what I was thinking. Thanks ðŸ™‚
4. XanthosNZ
Cancerous Bus Crash
16 May '06 12:27
Originally posted by flyUnity
Ok, I got it now, I dont know what I was thinking. Thanks ðŸ™‚
Hope you are never plotting a course for a plane I'm on.
5. 16 May '06 21:07
Originally posted by XanthosNZ
Hope you are never plotting a course for a plane I'm on.
Dont worry, Computers plot my courses now. They give me headings, bearings, relative winds, and magnetic error variations all with with only pressing a few buttons on the computer. ðŸ˜›
6. 20 May '06 17:59
Originally posted by flyUnity
Dont worry, Computers plot my courses now. They give me headings, bearings, relative winds, and magnetic error variations all with with only pressing a few buttons on the computer. ðŸ˜›
i hope the buttons are not plus or minus buttons lols

thanks for the laugh
7. 23 May '06 18:30
Originally posted by flyUnity
Dont worry, Computers plot my courses now. They give me headings, bearings, relative winds, and magnetic error variations all with with only pressing a few buttons on the computer. ðŸ˜›
press a wrong button, how do you know you're not flying off into oblivion?
8. 24 May '06 01:48
Hey, Im not that dumb. Flying is easier then driving a car.
9. 26 May '06 09:041 edit
10. sonhouse
Fast and Curious
30 May '06 00:32
Originally posted by flyUnity
Hey, Im not that dumb. Flying is easier then driving a car.
Especially if you are in a plane.
11. Bowmann
Non-Subscriber
30 May '06 01:46
I learnt that a minus times a minus is a plus when I was four months old.
12. 30 May '06 02:07
Originally posted by Bowmann
I learnt that a minus times a minus is a plus when I was four months old.
Slow learner.
13. AThousandYoung
All My Soldiers...
30 May '06 02:17
Originally posted by flyUnity
Hey, Im not that dumb. Flying is easier then driving a car.
Umm...are you telling us it's ok that you're a pilot even though driving is too difficult for you?
14. Bowmann
Non-Subscriber
30 May '06 02:34
Originally posted by Gastel
Slow learner.
I was busy studying philosophy.
15. 30 May '06 03:56
Originally posted by Bowmann
I was busy studying philosophy.
"studying"? "philosophy"? oxymoron?