| Author | Message | Time |
|---|---|---|
| hismajesty | I am a bit confused on this problem, even though it appears to be faily simple. Any help is appreciated. [pre] 1-3x 2 ------ + ---- x-6 2x+1[/pre] Here's what I've done so far.. I multiplied the fraction on the left of the addion sign by: [pre] ( 2x+1 ) (--------) ( 2x+1 )[/pre] And that on the right side by: [pre] (x-6) (----) (x-6)[/pre] Which gives me: [pre] (1-3x)(2x+1) 2(x-6) ---------------- + -------------- (x-6)(2x+1) (x-6)(2x+1)[/pre] After Foiling I've concluded that the answer is: [pre] -x-6x^2-11 -------------- (x-6)(2x+1) [/pre] However, I'm sure this is incorrect as I started getting confused while looking at notes/doing what I thought was correct. Thanks in advance | March 15, 2004, 11:10 PM |
| Yoni | Almost correct. You're correct up to (and including) this part: [quote author=hismajesty link=board=36;threadid=5799;start=0#msg49602 date=1079392248] Which gives me: [pre] (1-3x)(2x+1) 2(x-6) ---------------- + -------------- (x-6)(2x+1) (x-6)(2x+1)[/pre][/quote] Now: [color=yellow](1-3x)(2x+1) =[/color] 2x - 6x^2 + 1 - 3x [color=yellow]= -6x^2 - x + 1[/color] [color=cyan]2(x-6) = 2x - 12[/color] Adding them gives: [color=yellow](1-3x)(2x+1)[/color] + [color=cyan]2(x-6)[/color] = [color=yellow]-6x^2 - x + 1[/color] + [color=cyan]2x - 12[/color] = [color=lightgreen]-6x^2 + x - 11[/color] The final answer is: [color=red]-6x^2 + x - 11 ------------------ (x-6)(2x+1)[/color] Which cannot be reduced further. Basically you were correct except for the sign on the "x". Edit: Formatting. | March 16, 2004, 3:13 PM |
| hismajesty | hmm, today in class I worked this problem with another student and we got a different answer. Here's what we/I did why is this not correct? Again, the problem is: [pre] 1-3x 2 ------ + ---- x-6 2x+1[/pre] As before I multiplied either side by the opposite sides denominator again giving me: [pre] (1-3x)(2x+1) 2(x-6) (1-3x)(2x+1) + 2(x-6) ---------------- + --------------- = ---------------------------- (x-6)(2x+1) (2x+1)(x-6) (2x+1)(x-6)[/pre] I then crossed out the (2x+1) and the (x-6) leaving: -3x+3. Why is this incorrect? | March 16, 2004, 7:58 PM |
| Yoni | The "crossing out" part is incorrect. You can't cross out if you have a sum, only if you have a product. | March 16, 2004, 8:35 PM |
| hismajesty | Yep, I noticed that and went back and corrected it, ended up getting the answer you gave. Thanks for the help. | March 17, 2004, 1:09 AM |