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Need Help please (test in two days)!?

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Schmitty

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I am having trouble seeing how to exactly arrive at the right answers for math problems #19 and #43 on the marine test prep (getting nervous since the test is 2 days away !!). On #19 equation x=1/2t(y-z) which is reported to be the same as y=2x/t=z. On #43 x^2-x-2/(x+1)answer x-2. How did they arrive at these answers? Also does anyone know a good way to do square roots of odd numbers? And finally is the ASTB gouge still current? Any timely help would be greatly appreciated!!
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version2point0

Registered User
#43: the top part of the equation reverse FOIL's out to (x+1)(x-2) (remember FOIL means First Inside Outside Last) so if you were to perform that to check your reverse FOIL then (x+1)(x-2)=x^2-x-2. if you have (x+1)(x-2)/(x+1) then you can divide away the (x+1) on top and bottom so you are left with only (x-2)

#19: i think you may ahve mistypped the answer for this one because there are two = signs. im going to assume you meant the answer is y = 2x / (t+z). i will work on it and have an answer in an hour or two (i have to go to school, but ill be able to answer from there).

and what do you mean by square roots of odd numbers. do you mena irrational answers? because odd numbers can sometimes be evenly square rooted i.e. root9 = 3

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version2point0

Registered User
i tired, but i really think #19 is mistyped. please recheck the problem, give me the beginning, and what the question is looking for (solve for y or whatever) and ill work it out for you :)

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TNWhiskey

2ndLt Charlie Co TBS
#43 is a problem in which you have to factor the top of the equation...then you can cancel out like terms.


x^2-x-2 can be factored into (x-2)(x+1) so you have x+1 in the numerator and the denominator so they can be cancelled leaving x-2.

Factoring works this way...you know you'll have (x)(x) because of the x^2 so write (x ?)(x ?)...Now what times what would give you a -2??? Either 2 * -1 or 1 * -2...so you know that one set of these numbers will fit into the second part of the parentheses...the clue is that with a (-x) in the middle of the equation you know what you use a -2 because -2 + 1 = -1...or since you're adding -2x + (1)x = -x.

(x-2)(x+1)...To check your work, work backwards by multiplying the terms in this manner (First, Oustside, Inside, Last) or known as the FOIL method...

So x*x, x*1, -2*x, -2*1...the answer is x^2+1x-2x-2 or simplying the x's as x^2 - x - 2. You have the original equation...

Here's a little harder one I've made up...2x^2 - 2x - 12 / (x + 2)

The trick to factoring the numerator here is to factor out any whole number multiple first...or 2 in this case...So 2(x^2 - x - 6) / (x + 2)

Now factor as before 2(x ?)(x ?)/ (x+2)...factors of -6 are: -1,6; -6,1; 2,-3; -3,2...which two will leave you a -1x when added to together?...(-3,2)
So 2 (x-3)(x+2) / (x+2)....cancel the (x+2)'s leaving an Answer of

2(x-3).

The main trick to figuring out a simplified math test such as the ASTB is to understand that almost always the denominator will be one of the factors in the numerator allowing for cancelling...Knowing this will help save a few second in solving.

Hope that helps.
 
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Schmitty

Registered User
Thanks so much for all your help guys! I can't believe I did not see #43. As for #19 they are asking x=1/2t(y-z) is equivelant to equation y= ? The answer key says it is equivalent to y=2x/t+z. When I do it I get y=2x/t+2, so what gives? Is this a typo on their part or am I doing something wrong? Also do you guys know if the gouge is still valid? There was a rumor posted on this forum that they were changing the test, any truth to this? Thanks once again fellas!
 
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Eteled

Registered User
Their answer for #19 is correct. Remember your "order of operations".

x = 1/2*t*(y-z) -> 2*x = t*(y-z) -> 2*x/t = y-z -> 2*(x/t)+z = y

I added the () to make it clear that +z wasn't part of the denominator.

Don't worry about funky radicals. You won't have to deal with them. In some of the questions they end up with a funky radical, but they obtained this by "simplifying" the answer. Such a case is when they reduced sqrt(27).

sqrt(27) = sqrt(9*3)= sqrt(9)*sqrt(3), the nine can now be rooted! sqrt(27) = 3*sqrt(3).

This is the extent of anything you'll see.

I took the ASTB on 10/10/03 and it was very similar to the gouge here. The tester did mention that it was a pretty old version though. The math section shouldn't be a problem. Watch the reading section. I'm pretty sure that's where I missed questions. Do not assume anything from the passages!
 
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Schmitty

Registered User
Thanks for the help Eteled! Once again I can't believe I did not see how #19 worked out. Also what type of reading questions did they ask for example:
-Fill in the sentence with the correct word from the list
-Determine which word is incorrectly used in a quotation and pick the right word to replace it
-Determine which statement most nearly conveys the meaning of the passage

How did you score on the test? I am getting very nervous because I tested myself on the MVT section out of the arco book and ran out of time. Unfortunetly due to my rushing in order to finish I made stupid mistakes. Any advice?
 
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Eteled

Registered User
Study the reading sections in the ARCO books. I felt that these were a bit more difficult than the ASTB. The types of questions are the same between them. Bring a watch in with you. They let me and I used to it make sure I was on pace (you should know how much time you have for each question in each section). I scored an OAR of 66. I think I missed eight total between the Math/Verbal and Mechanical sections.
 
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