1 Word problem and 1 function problem, PLEASE HELP ME

[murkr]

you guys are all very good at math, i love these forums. I understand more things here then i do most the time in class, i have a test coming up and i really need help understanding these 2 problems, can someone please solve these problems and explain the steps, i would really appreciate it.

i got a review packet, i scanned the problems because i dont know how to type them
http://img694.imageshack.us/img694/9811 ... 222222.jpg

problem #28 and #29 are the ones im having problem with and need the help.

also was i correct with #27? was it A? thanks everyone

 

[Deleted member 4993]

you guys are all very good at math, i love these forums. I understand more things here then i do most the time in class, i have a test coming up and i really need help understanding these 2 problems, can someone please solve these problems and explain the steps, i would really appreciate it.

i got a review packet, i scanned the problems because i dont know how to type them
http://img694.imageshack.us/img694/9811 ... 222222.jpg

problem #28 and #29 are the ones im having problem with and need the help.

also was i correct with #27? was it A?

No - that is incorrect. How did you arrive at your answer?

thanks everyone

 

[BigGlenntheHeavy]

\(\displaystyle 27 \ is \ C, \ 28 \ is \ D, \ and \ 29 \ is \ C.\)

\(\displaystyle Now \ I \ gave \ you \ the \ correct \ answers, \ you \ figure \ them \ out, \ a \ good \ exercise \ for \ you.\)

 

[murkr]

\(\displaystyle 27 \ is \ C, \ 28 \ is \ D, \ and \ 29 \ is \ C.\)

\(\displaystyle Now \ I \ gave \ you \ the \ correct \ answers, \ you \ figure \ them \ out, \ a \ good \ exercise \ for \ you.\)

awesome thank you, i really appreciate that, i wish it was the other way around though haha. on the test its going to be similar questions or maybe even the same ones "its been before", i wouldnt of asked these questions if i really wasnt stumped, iv been spending around 2 hours a night for the past 7 days working on this packet, it has 45 problems and i got most of them but around 10 of those im having a really big problem with, thus coming here and asking you guys for some advice/help. dont get me wrong i really appreciate your answers that helps ALOT, i just dont know how to work backwards.
EDIT: i figured out how to do them, but not #27, i dont see how you got C on #27.

 

[Denis]

EDIT: i figured out how to do them, but not #27, i dont see how you got C on #27.

2^(1 - x) = 2 / 2^x

OK? :idea:

Don't forget that a^p * b^p = (ab)^p

 

[Deleted member 4993]

\(\displaystyle \left (\frac{6}{7}\right )^x \ \ = \ \ 2^{1-x}\)

\(\displaystyle ln\left [\left (\frac{6}{7}\right )^x \right ]\ \ = \ \ ln\left [2^{1-x}\right ]\)

\(\displaystyle x \cdot ln\left [\frac{6}{7} \right ]\ \ = \ \ (1-x) \cdot ln [2]\)

\(\displaystyle x \cdot (ln\left [\frac{6}{7} \right ] + \\ ln [2])\ \ = \ \ ln [2]\)

and so on...

 

[murkr]

\(\displaystyle \left (\frac{6}{7}\right )^x \ \ = \ \ 2^{1-x}\)

\(\displaystyle ln\left [\left (\frac{6}{7}\right )^x \right ]\ \ = \ \ ln\left [2^{1-x}\right ]\)

\(\displaystyle x \cdot ln\left [\frac{6}{7} \right ]\ \ = \ \ (1-x) \cdot ln [2]\)

\(\displaystyle x \cdot (ln\left [\frac{6}{7} \right ] + \\ ln [2])\ \ = \ \ ln [2]\)

and so on...

ok thank you that makes sense, but with your solution it looks like it is leading to answer B right? when a friend of mine showed me he got answer C. but maybe your work will lead to that i dont know what to do from there. so does your work lead to answer B or C? thanks for your help, i really appreciate it.

 

[Deleted member 4993]

ok thank you that makes sense, but with your solution it looks like it is leading to answer B right? when a friend of mine showed me he got answer C. but maybe your work will lead to that i dont know what to do from there. so does your work lead to answer B or C? thanks for your help, i really appreciate it.

If you do not know how to finish - after I have done 90% of the problem - you need serious face-to-face assistance. Talk to your teacher and brush up your elementary algebra. A good place to start would be:

http://www.purplemath.com/modules/solvelin.htm

 

[Denis]

Don't listen to him Murky; Subhotosh is mean, should have done 100% of your work, not only 90% :shock: