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Math Question


Mr. Showtime

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I'm sure this is very simple, but I don't understand. It's a sample question off an "Elementary Algebra" packet.

 

Question: 16x - 8 =

 

The choices I was given we're

 

(A) 8x

"B" 8(2x-x)

"C" 8(2x-1)

(D) 8(2x-8)

 

The packet tells me "C" is the right answer. How do you get to that? I can see why the answer isn't "A". I understand "B" simply to me because there cannot be that many x's in the answer. However, I don't get "C" or "D".

 

:crying = me because I cannot figure out something apparently so simple.

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Well, it's quite simple really.

 

By ways of the Distributive property, 8(2x-1) would make it 16x-8, simply by taking the 8 and multiplying by both numbers in the parentheses.

 

8 x 2x = 16x

8 x 1 = 8

 

A gives you an equation of 16x - 8 = 8x, which boils down to 2x - 8.

B gives you 16x - 8x, which is simply 8x.

C gives you the answer in the question, 16x - 8.

D gives you 16x - 64.

Edited by SoxFan1
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QUOTE(SoxFan1 @ Jun 24, 2007 -> 12:46 AM)
Well, it's quite simple really.

 

8(2x-1) would make it 16x-8, simply by taking the 8 and multiplying by both numbers in the parentheses.

 

8 x 2x = 16x

8 x 1 = 8

 

Oh lord, I am f***ed.

 

I figured you had to multiply the 8 x 2 but I couldn't figure out how the hell they got the one.

 

Better than me at graphics and math... :bang

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QUOTE(Mr. Showtime @ Jun 24, 2007 -> 12:49 AM)
Oh lord, I am f***ed.

 

I figured you had to multiply the 8 x 2 but I couldn't figure out how the hell they got the one.

 

Better than me at graphics and math... :bang

Why are you doing beginners algebra during the summer in the 1st place?

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Yeah, C is the correct answer. 16x-8=8(2x-1) because 16x/8=2x and 8/8 =1. However, if you have a problem like 3x/9x-5, it is completely illegal to break it into the math sentence 1/3-3/5x. BTW if anyone has a math question in differential equations or a lower class(Calculus, college algebra, trig, etc.) feel free to PM me and I'll answer if I have the time. I can't help with statistics, so please don't PM me on those questions.

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QUOTE(SoxFan1 @ Jun 24, 2007 -> 12:52 AM)
Why are you doing beginners algebra during the summer in the 1st place?

 

23 now, and finally going to college. I know, I'm a goof for waiting..

 

I have to take a test to see where I'm at so they know what level to start me at. So, as I said prior, I'm in big trouble.

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QUOTE(Mr. Showtime @ Jun 24, 2007 -> 12:55 AM)
23 now, and finally going to college. I know, I'm a goof for waiting..

 

I have to take a test to see where I'm at so they know what level to start me at. So, as I said prior, I'm in big trouble.

Those placement tests aren't very hard. If you have a general understanding of algebra, you should be fine.

 

QUOTE(Heads22 @ Jun 24, 2007 -> 12:59 AM)
I've gone thru calculus and beginners stats.

 

No more math and I'll be happy.

No Cal for me, but I took AP Stats. Pretty easy, outside of those damn formulas.

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QUOTE(SoxFan1 @ Jun 24, 2007 -> 01:00 AM)
Those placement tests aren't very hard. If you have a general understanding of algebra, you should be fine.

 

I know it appears as if I don't.. :P

 

I've just been out of it for so long that I had no idea what the hell was going on with this one.

 

Like another example was:

 

x + 20 = 2x + 60

 

However, I knew how to break that down and get -40 as the answer.

 

Seriously, thanks for answering everyone.

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