/sci/ - Science & Math » Thread #12897227

484KiB, 1090x3712, 20210329_002539.jpg

View Same Google iqdb SauceNAO

Anonymous Mon 29 Mar 08:30:50 2021 No.12897227 View Reply Original Report

Quoted By: >>12897234 >>12897249 >>12897251 >>12897416 >>12899357

Explain this to me because I'm fucking retarded.

My answer is 20-4x / x +5

What am I missing where the correct answer is -4(x-5) / x +5?

What step am I fucking up to not get the numerator to show up like the correct answer?

Anonymous

Anonymous Mon 29 Mar 2021 08:33:06 No.12897231 Report

Quoted By: >>12897240

Why don't you simplify the denominator by multiplying one of the fractions by -1/-1

Anonymous

Anonymous Mon 29 Mar 2021 08:34:57 No.12897234 Report

Quoted By:

>>12897227
Is it because I canceled out (x-5)/(x-5) = 1 instead of (5-x)/(x-5) = -1? Because if so that is fucking stupid.

Anonymous

Anonymous Mon 29 Mar 2021 08:35:58 No.12897240 Report

Quoted By: >>12897266

>>12897231
What do you mean?

Anonymous

Anonymous Mon 29 Mar 2021 08:41:31 No.12897249 Report

Quoted By: >>12897265

>>12897227
20-4x / x +5 = -4(x-5) / x +5

Just factor a -4 out of the numerator...

Anonymous

Anonymous Mon 29 Mar 2021 08:43:09 No.12897251 Report

Quoted By: >>12897281

>>12897227
lol wtf, all you had to do was factor out the -1 from the x-5 from the very first step, and it would've saved you 5 hours.

Anonymous

Anonymous Mon 29 Mar 2021 08:47:34 No.12897265 Report

Quoted By: >>12897466 >>12897516

>>12897249
I get that. What I'm asking is 'why?'

Going from 4(5-x) to -4(x-5) to get the "right" answer is stupid. Specifically if the path I took to simplify doesn't lead me there logically. Yes 4(5-x) = -4(x-5) but I'm missing where simplifying the problem gets you the latter without forcing it.

Anonymous

Anonymous Mon 29 Mar 2021 08:47:48 No.12897266 Report

Quoted By: >>12897285

>>12897240
I mean what I said, take one of the fractions in the denominator and multiply it by -1/-1

Anonymous

Anonymous Mon 29 Mar 2021 08:53:33 No.12897281 Report

Quoted By: >>12897288

>>12897251
That makes no sense. The objective is to eventually rewrite as reciprocal and then multiply the rational expressions.

Do you mean to make it so the denominator is:

(6/5-x)-(5/5-x)? Then it becomes (4/x+5) * (5-x/1) which is the same damn answer (20-4x/x+5)

Anonymous

Anonymous Mon 29 Mar 2021 08:54:48 No.12897285 Report

Quoted By: >>12897288

>>12897266
See
>>12897266

Anonymous

Anonymous Mon 29 Mar 2021 08:55:49 No.12897288 Report

Quoted By: >>12897367

>>12897285
I meant >>12897281

Anonymous

Anonymous Mon 29 Mar 2021 09:51:46 No.12897367 Report

Quoted By:

>>12897288
Yes that's correct I was saying that's a lot faster

Anonymous

Anonymous Mon 29 Mar 2021 10:33:55 No.12897416 Report

Quoted By:

>>12897227
You have to be 18 to post here

Anonymous

Anonymous Mon 29 Mar 2021 10:52:25 No.12897466 Report

Quoted By:

>>12897265
>Going from 4(5-x) to -4(x-5) to get the "right" answer is stupid.
that is not stupid at all
nobody really cares about minor details like that in the final result though

wait until you hear about
>completing the square
>adding and subtracting the same value
>tons of other small operations like this

Anonymous

Anonymous Mon 29 Mar 2021 11:08:19 No.12897516 Report

Quoted By:

>>12897265
>Going from 4(5-x) to -4(x-5) to get the "right" answer is stupid
>Specifically if the path I took to simplify doesn't lead me there logically.
did you think that solving a math problem is a completely deterministic process where every next step is unambiguous AND obvious? anon...

Anonymous

Anonymous Mon 29 Mar 2021 20:13:41 No.12899357 Report

Quoted By: >>12899831

>>12897227
Simplify in turns
Top becomes 4/(x+5)
Bottom becomes 1(5-x)
Divide:
4(5-x) / (x+5)

QED

Anonymous

Anonymous Mon 29 Mar 2021 22:21:03 No.12899831 Report

Quoted By:

>>12899357
I agree and that is my answer as shown in the pic.

However, the My Math Lab test this question was on says the answer is
-4(x-5) / (x+5)
I understand that it's same as saying 4(5-x), I just don't get what path of simplifying the equation they took to get there.
Maybe I'm overthinking it by being bothered with getting the question wrong.

Capcode	All Only User Posts Only Moderator Posts Only Admin Posts Only Developer Posts
Show Posts	All Only With Images Only Without Images
Deleted Posts	All Only Deleted Posts Only Non-Deleted Posts
Ghost Posts	All Only Ghost Posts Only Non-Ghost Posts
Post Type	All Only Sticky Threads Only Opening Posts Only Reply Posts
Results	All Grouped By Threads
Order	Latest Posts First Oldest Posts First

Your latest searches