Perform indicated operation: ((3t-1)/(t^2+2t-3))/((t+4)/(1-t

E

evan399

New member
Joined
Sep 24, 2007
Messages
39
Perform the indicated operation and simplify when possible

((3t-1)/(t^2+2t-3))/((t+4)/(1-t))

Is the answer

(-t^2-4t-13)/((t+3)(t-1))
 
Re: Perform indicated operation: ((3t-1)/(t^2+2t-3))/((t+4)/

evan399 said:
Is the answer (-t^2-4t-13)/((t+3)(t-1))
Click to expand...
Sorry, no. What were your steps? Please start with flipping the division and doing the factoring:

. . . . .[(3t - 1) / ((t + 3)(t - 1))] * [-(t - 1)/(t + 4)]

...and show where you went from there. Thank you! :D

Eliz.
 
This is what I did

((3t-1)/(t+3)(t-1))-((t+4)(t+3))/(t-1)(t+3))
I multiplied the top and bottom of everything after the subtraction sign.

Then I got

(3t-1-t^2-7t-12)/((t+3)(t-1))
I simplified and got what I originally posted.
 
Re: Perform indicated operation: ((3t-1)/(t^2+2t-3))/((t+4)/

evan399 said:
Perform the indicated operation and simplify when possible

((3t-1)/(t^2+2t-3))/((t+4)/(1-t))

Is the answer

(-t^2-4t-13)/((t+3)(t-1))
Click to expand...

I assume your problem is:

{(3t-1)/(t^2+2t-3)} / {(t+4)/(1-t)}

this is fraction divided by fraction.

How would you evaluate:

(7/4) / (35/72)

You would flip the bottom fraction and re-write the problem as:

(7/4) * (72/35)

then simplify.....
 
Sorry I messed up on writing the original problem. It is

((3t-1)/(t^2+2t-3)) - ((t+4)(1-t))

It is a fraction subtracted by another fraction.[/b]
 
evan399 said:
Sorry I messed up on writing the original problem. It is

((3t-1)/(t^2+2t-3)) - ((t+4)(1-t))
Click to expand...
Factoring the denominators, you got:

. . . . .t<sup>2</sup> + 2t - 3 = (t + 3)(t - 1)

. . . . .1 - t = -1(t - 1)

So the common denominator is then (t - 1)(t + 3). You converted the second fraction to this common denominator by multiplying top and bottom by (t + 3):

. . . . .(t + 4)(t + 3) = t<sup>2</sup> + 7t + 12

Note: The "minus" on the denominator of the second fraction can "go up top", thus turning the subtract of terms into addition of terms. This give you:

. . . . .(3t - 1)/[(t + 3)(t - 1)] + (t<sup>2</sup> + 7t + 12)/[(t + 3)(t - 1)]

. . . . .(t<sup>2</sup> + 7t + 3t + 12 - 1) / [(t + 3)(t - 1)]

Simplify. Factor the numerator. See if anything can cancel. :D

Eliz.
 
evan399 said:
So I got for an answer

((t+10)(t+1))/((t+3)(t-1)) right?
Click to expand...
No. Please show your work and reasoning, so we can try to find where you're going wrong.

Eliz.
 
evan399 said:
No, wait it should be
((t+11)(t+1))/((t+3)(t-1))
right? No
Click to expand...

Please show us your step in arriving at those factors - in detail.
 
This is what I did

((3t-1)/(t^2+2t-3))-((t+4)/(1-t))
((3t-1)/(t-1)(t+3))+((t^2+7t+12)/(t+3)(t-1))
then I combined them and got
(t^2+7t+3t+12-1)/((t+3)(t-1)
so, (t^2+10t+11)/((t+3)(t-1))
 
stapel said:
evan399 said:
Sorry I messed up on writing the original problem. It is

((3t-1)/(t^2+2t-3)) - ((t+4)(1-t))
Click to expand...
Factoring the denominators, you got:

. . . . .t<sup>2</sup> + 2t - 3 = (t + 3)(t - 1)

. . . . .1 - t = -1(t - 1)

So the common denominator is then (t - 1)(t + 3). You converted the second fraction to this common denominator by multiplying top and bottom by (t + 3):

. . . . .(t + 4)(t + 3) = t<sup>2</sup> + 7t + 12

Note: The "minus" on the denominator of the second fraction can "go up top", thus turning the subtract of terms into addition of terms. This give you:

. . . . .(3t - 1)/[(t + 3)(t - 1)] + (t<sup>2</sup> + 7t + 12)/[(t + 3)(t - 1)]

. . . . .(t<sup>2</sup> + 7t + 3t + 12 - 1) / [(t + 3)(t - 1)]

Simplify. Factor the numerator. See if anything can cancel. :D

Eliz.
Click to expand...
Something seems wrong with that, Eliz: doesn't "check back";
why have you got "denominators" as plural; and "2nd fraction"?

But I'm too lazy to work it out!
Plus seems to me that the original is as simplified as can be.
 
The problem should read

((3t-1)/(t^2+2t-3))-((t+4)/(1-t))

so what I did was
((3t-1)/(t+3)(t-1))-((t+4)/(1-t)
((3t-1)/(t+3)(t-1))+((t^2+7t+12)/(t+3)(t-1)
then combine to get (t^2+10t+11)/(t+3)(t-1)
then (t+11)(t+1)/(t+3)(t-1) is the answer
right???
 
evan399 said:
The problem should read
((3t-1)/(t^2+2t-3))-((t+4)/(1-t))
Click to expand...
WHAT! This is the 3rd time you've changed it.
You get zilch from me.

Sorry Eliz: looks like you had properly "guessed" it!
 
You must log in or register to reply here.
Top