Is (x+1)(x-1)/(1-x)?

Question

did you memorize the answer?? It's -(x+1)

[x^2 -1]/(1-x) can't really be simplified by anything that I leanred and I am in calculus now ...so I just used synthetic division ...and I got -(x+1) ...but should I memorize this ...do most people memorize this solution ...or no?

Answer 1

(x + 1) (x - 1) / (1 - x)
- (1 - x) (x + 1) / (1 - x)
- (x + 1)
Don`t memorise -----follow basic rules of Algebra as shown above.

Answer 2

It can easily be simplified.

(1-x)=-1(x-1)

(x+1)(x-1)/(1-x)=(x+1)(x-1)/(-1(x-1))=(x+1)/-1=-(x+1)

There is no need to memorize this solution. What you need to do is remember the various "tricks" that can be done to change the appearance of expressions. This is very important in Calculus.

Answer 3

Never needed to memorize it, really. The important thing to remember here is that factoring -1 from an expression swaps the signs...

(a-b) = (a + -b) = (-1)(-a + b) = (-1)(b-a)

Answer 4

No, most people do not memorize this they factor the denominator.

(1-x) = (-x + 1) = -1(x-1) so

[(x+1)(x-1)]/ -1(x-1)

the (x-1)s cancel each other out and you are left with

(x+1) /-1 = -(x+1)

Answer 5

it's not a "memorize" thing .. just learn to SEE that

(x - 1) = - (1 - x)



you might think of this as "pattern recognition"
"two symbols connected with a "-" sign ..."

and the same two symbols connected with "-" .. but in a different order

Answer 6

Just memorize the part where (x-1)/(1-x)=-1

Answer 7

as far as I know, the answer should be -(x-1) or 1-x... and no, I did not memorize the answer... I solve the problem...

ooppss... sorry i made a mistake... I'm really careless with signs...lol... your answer is correct....

Answer 8

Keep this in mind:
(1 - x) = (-x + 1) = - (x - 1)

So:
[(x + 1)(x - 1)] / (1 - x)
= [(x + 1)(x - 1)] / [-(x - 1)]
= (x + 1) / -1
= -(x + 1)

Answer 9

You don't need to memorize anything.

a*b / -b is always -a
.