SAT Math Problem Help

[Atlas14]

I was wondering if anyone could help me with this problem. For some reason I just don't know how to solve it. I know the answer, cause I looked it up in the book, but can't figure out how to do it. Thanks

 

[FrantzX]

Let's see...

f(x) = (x^2) - x
f(a) = (a^2) - a
f(a-2) = ((a-2)^2) - (a-2) = (a^2 -4a + 4) -a + 2 = a^2 - 5a + 6

f(a) = f(a-2)
a^2 - a = a^2 - 5a + 6
-a = -5a + 6
4a = 6
a = 6/4 = 3/2

 

[Atlas14]

Thanks FrantzX! I know I've done functions like this before, but its been a while. I had been looking at this stupid problem for many hours, and decided I felt too dumb to keep trying. Thanks again!

 

[newfangle]

I find that problem offensive. Stupid vacuous truths.

Actually the correct response would be:
If x=x^2 - x FOR ALL x, you could say that a is equal to whatever the hell you want it to be, since the anticedent condition is only met for x=2

 

[Perfection]

How is the anticedent condition only met for two?

 

[newfangle]

Because it means 2x=x^2
A condition only met in the reals for 2. Or 0.

 

[The Last Conformist]

It took me a while to figure out that the thin circles were an operator and not merely orthographic highlighting.

 

[Perfection]

Because it means 2x=x^2
A condition only met in the reals for 2. Or 0.

No, as TLC said the circle is an operator

It's circle(x)=x^2-x

 

[newfangle]

What kind of effed up notation is that? Bah!

 

[Aphex_Twin]

So a good SAT score is what it takes to get into a good American university, right?

 

[Perfection]

What kind of effed up notation is that?

They do this kind of thing all the time, make up thier own operators

So a good SAT score is what it takes to get into a good American university, right?

It's factor, but by no means is everything (though many do have lowest requirements) also in some schools they look at the ACT instead (especially in the midwest)

 

[The Last Conformist]

What kind of effed up notation is that? Bah!

There seems to exist a species of textbook writers who think that conventional notation will scare away younger students (SAT is HS, right?). Whether they're right or not, there remedies seem to be invariably confusing to me.

 

[Perfection]

There seems to exist a species of textbook writers who think that conventional notation will scare away younger students (SAT is HS, right?). Whether they're right or not, there remedies seem to be invariably confusing to me.

Well, I think the point is to see if kids can work with new symbolic operators and stuff.

It makes sense to me, in college level classes you have to deal with new operators springing up occasionally.

 

[newfangle]

Even when I was taking the simplistic Canadian high school math courses they didn't refrain from using f(x) or whatnot. This is just bizarre.

 

[newfangle]

And that thing is totally not a circle. What the hell?

 

[Perfection]

Even when I was taking the simplistic Canadian high school math courses they didn't refrain from using f(x) or whatnot. This is just bizarre.

As are the floor and ceiling functions...

And that thing is totally not a circle. What the hell?

Fine ellipse(x)=x^2-x, happy?

 

[Aphex_Twin]

Anyone have a kind of syllabus on the thing? Is it THAT simple? The Romanian Bacalaureat for instance consists of 7 tests that are not a dream to take.

 

[Perfection]

Anyone have a kind of syllabus on the thing? Is it THAT simple? The Romanian Bacalaureat for instance consists of 7 tests that are not a dream to take.

http://www.collegeboard.com/student/testing/sat/about.html

 

[newfangle]

Fine ellipse(x)=x^2-x, happy?

Or a parabola, perhaps? (Unless there is another freakin ambiguity in the symbolization.)

 

[Perfection]

Or a parabola, perhaps?

Parabolas are open, this is clearly not upen despite the fact that the operation involves a binomial.

(Unless there is another freakin ambiguity in the symbolization.)

Well, I think it's obvious that they meant the same symbol throughout the problem