Algebra Help?

This is the same exact question as I posted before, but I really need an answer, because I have to give like 120 questions of work by tomorrow (I didn't procrastinate, could tell you that much...)





5. Which of the following represents the statement: "Seven less than one-third of n is equal to seven more than 3 times m?"





(A) 1/3n + 7 = 3m - 7


(B) 3n + 7 = 1/3m - 7


(C) n = 9m + 28


(D) 3n - 7 = 1/3m + 7


(E) 1/3n = 3m - 14





17. What is the value of 2z^2 - 2/z^2 if 2z - 2/z = 4?





*I believe this should be an answer without a square root because SAT's don't make you do square roots are fill in answers.





14. Becky opened a savings account that earns a fraction x of its balance in interest every year. Three years ago Becky deposited $800 into the account, and has not deposited or withdrawn any money since. If she has earned 126.10 in interest, what is the value of x?





(A) 1/4


(B) 1/5


(C) 1/10


(D) 1/20


(E) 1/25





No typos.





URGENT!!!|||5) 1/3 * n - 7 = 3*m + 7 is the statement as given.





=%26gt; add 7 to both sides





1/3 * n = 3*m + 14





Choice (E) - if you made a typo on that one, as the other choices are definitely not correct. Or, you made a typo on another one. I am not sure.





17) 2z - 2/z = 4





=%26gt; divide by 2





z - 1/z = 2





=%26gt; square both sides





(z - 1/z)^2 = 4





=%26gt; FOIL





z^2 - 1/z^2 - 2 = 4





=%26gt;





z^2 - 1/z^2 = 6





=%26gt; multiply by 2 on both sides





2z^2 - 2/z^2 = 12.





18)





year 1: She earns 800x in interest, thus having 800 + 800x = 800(1+x) at the end of one year





year 2: She earns 800(1+x) * x in interest, thus having 800(1+x) + 800x(1+x) = 800(1+x)^2 at the end of the second year.





Following similar reasoning, she will have 800(1+x)^3 by the end of year 3.





Thus, 800(1+x)^3 = 800 + 126.10





=%26gt;





(1+x)^3 = 1.157625





=%26gt;





1 + x = 1.05





=%26gt;





x = 0.05 = 1/20.


Choice (D)|||5 is E|||5) n/3 - 7 = 3m + 7





n/3 = 3m + 14





17) 2z - 2/z = 4





place all on one side and equate to zero





2z - 2/z - 4 = 0





divide by 2 and multiply by z throughout





z^2 - 2z - 1= 0





factorise and then plug in the values into your formula|||5 is actually B...read through it and you'll understand that it corresponds to "seven less than 1/3 of n is equal to seven more than 3m"





and i believe 14 is B





you need to be more clear on #17





Don't just stay on this problem, move on and come back to it later...





If you need any more help Im me on aim at Dunit0001