How does &#x2212;<!-- − --> 1 x &#x2212;<!-- − --> 2 </

vortoca

vortoca

Answered question

2022-07-07

How does 1 x 2 + 1 x 3 become 1 2 x 1 3 x
I'm following a solution that is using a partial fraction decomposition, and I get stuck at the point where 1 x 2 + 1 x 3 becomes 1 2 x 1 3 x
The equations are obviously equal, but some algebraic manipulation is done between the first step and the second step, and I can't figure out what this manipulation could be.
The full breakdown comes from this solution
1 x 2 5 x + 6 = 1 ( x 2 ) ( x 3 ) = 1 3 ( 2 ) ( 1 x 2 1 x 3 ) = 1 x 2 + 1 x 3 = 1 2 x 1 3 x = n = 0 1 2 n + 1 x n n = 0 1 3 n + 1 x n = n = 0 ( 1 2 n + 1 1 3 n + 1 ) x n

Answer & Explanation

Aryanna Caldwell

Aryanna Caldwell

Beginner2022-07-08Added 11 answers

Each of the terms was multiplied by 1 1 , which is really equal to 1, so it's a "legal" thing to do:
1 x 2 + 1 x 3
= ( 1 ) 1 ( 1 ) ( x 2 ) + ( 1 ) 1 ( 1 ) ( x 3 )
= 1 2 x + 1 3 x
= 1 2 x 1 3 x
Frederick Kramer

Frederick Kramer

Beginner2022-07-09Added 7 answers

I am a grade 8 student, so I may not be able to explain really well.
First, I need to prove that 1 x 2 = 1 2 x
To prove, let's assume that "x" can be any number, for instance, I take x=8.
So by substituting,
1 x 2 = 1 8 2 = 1 6
And same for this,
1 2 8 = 1 6 = 1 6
Therefore, we have proven that 1 x 2 = 1 2 x
I also need to prove that 1 x 3 = 1 3 x
So by substituting,
1 8 3 = 1 5
and the same for this,
1 3 8 = 1 5 = 1 5 = 1 5
Therefore, we have proven that 1 x 3 = 1 3 x
By why it worked? The truth is, it is just having -1÷(-1)=1 (negative×negative=positive)(And anything times 1 is the same number)
So, from 1 x 2 to 1 2 x , they inserted both -1 for numerator and denominator as the following below.
1 x 2 = 1 x 2 = 1 ( 1 ) 1 ( x 2 ) = 1 x + 2 = 1 2 x
same goes to 1 x 3 = 1 3 x

Do you have a similar question?

Recalculate according to your conditions!

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?