Divide. Can someone please help? https://study.ashworthcollege.edu/access/content/group/38441f94-71d6-46e6-8dd7-ece73f5a6548/exam_11_files/mc009-1.jpg
@jim_thompson5910 do you know how to do this ?
The first step is to flip the second fraction and multiply so that gives you \[\Large \frac{x^2+2x+1}{x-2} \bullet \frac{x^2-4}{x^2-1}\] what's next?
ummm i really have no idea...
the next step is to factor each expression so x^2+2x+1 factors to ??
i am not understanding :(
are you able to factor x^2+2x+1
do you set it equal to zero?
have a look at this page http://www.purplemath.com/modules/factquad.htm
it gives an example
would it be (x + 1)(x + 1)?
good
factor x^2-4 to get ???
it might help to think of x^2-4 as x^2+0x-4
(x-2)(x+2).?
?????????
good, then x^2 - 1 factors to ???
(x - 1)(x + 1) ???
So \[\Large \frac{x^2+2x+1}{x-2} \bullet \frac{x^2-4}{x^2-1}\] turns into \[\Large \frac{(x+1)(x+1)}{x-2} \bullet \frac{(x-2)(x+2)}{(x-1)(x+1)}\]
is that the answer ?
then you do these cancellations \[\Large \frac{(x+1)(x+1)}{x-2} \bullet \frac{(x-2)(x+2)}{(x-1)(x+1)}\] \[\Large \frac{\cancel{(x+1)}(x+1)}{x-2} \bullet \frac{(x-2)(x+2)}{(x-1)\cancel{(x+1)}}\] \[\Large \frac{x+1}{x-2} \bullet \frac{(x-2)(x+2)}{x-1}\] \[\Large \frac{x+1}{\cancel{x-2}} \bullet \frac{\cancel{(x-2)}(x+2)}{x-1}\] \[\Large \frac{x+1}{1} \bullet \frac{x+2}{x-1}\] \[\Large \frac{(x+1)(x+2)}{x-1}\]
The cancellations work because dividing any expression by itself is 1 (example: 5/5 = 1)
Then 1*x = x, so the 1 effectively goes away
ok
can you help with this one ? simplify the rational expression. state any excluded values. x^2-x-6/x+2
factor the numerator to get ???
ummm (x+2) (x+2) idk this one
x^2-x-6 is the same as x^2-1x-6 so you have to find two numbers that multiply to -6 AND add to -1
@jim_thompson5910 It amazes me how well you teach. Sorry to interrupt.
Thank you for the compliment. It's greatly appreciated.
A.x - 3, where x 3 B. x-2 C.1/x- 2 , where x - 2 D.x - 3, where x -2 these are the answers i can choice from and and i am think it is B? is that correct or is it C?
wait i think i did my math wrong....
what did you get when you factored x^2-1x-6
it would be (x-3)(x-3) right?
-3 times -3 = 9 we want the two numbers to multiply to -6
(x-3)(-2)?
I think you meant (x-3)(x-2)
-3 times -2 = 6 again, we want -6
i am confused?
here are all of the ways to multiply to -6 -6 = -1*6 -6 = -2*3 -6 = -3*2 -6 = -6*1 which pair of factors adds to -1 ?
-3+2= -1
that -3 and +2 are then used to form the factorization of x^2-1x-6
x^2-1x-6 factors to (x-3)(x+2)
\[\Large \frac{x^2-x-6}{x+2}\] turns into \[\Large \frac{(x-3)(x+2)}{x+2}\] I'm sure you see what to do from here
(x-3) but out of the answers to pick what one would it be A.x - 3, where x neq 3 B. x-2 C.1/x- 2 , where x neq - 2 D.x - 3, where x neq -2
keep in mind that you cannot divide by zero
so you have to make sure the denominator isn't zero the denominator is zero when x = -2 since x+2 = 0 x = -2 so we must add the restriction that \(\Large x \neq -2\) to avoid division by zero.
x can be 3 since that doesn't make the denominator zero
so it would be D ?
yes
ok thank you!
np
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