Math education today (vanity)

Yahoo Answers ^ | 06/10/11 | self

[Da Coyote]

With all due respect, having such a useless question (along with multiple choices) is soooooo typical of something coming from an “education” major.

The problem is to solve for x and y. Any number of different methods will work...from simple steps to isolate a single x or y, to more complex steps such as using matrices.

But I know one thing for sure: No one in the West Wing Clown shop of felon/cretins, or the Dumb-O-Dent himself could solve it using any methods at all — except cheating.

[SoothingDave]

Select the best possible first step to solving the system by first eliminating the y variable.

5x - y = 5
7x - 3y = -1

OK. Watch me "eliminate" the y variable.

Take the first equation. Move the y to the right side and the 5 to the left side (changing signs):

5x - 5 = y

Plug in (5x - 5) for y in the second equation. Now the y variable is "eliminated."

7x - 3(5x - 5) = -1
7x - 15x +15 =-1
-8x + 15 = -1
8x = 16
x=2
y= 5x - 5
y= 10 - 5
y=5

x=2, y = 5

[Eldon Tyrell]

Needless complexity that adds no value.

Emphasis on knowing the specific names of methods to solve mathematical problems.

Apparent over-emphasis on the process and not the product.

In fact - viewed from where I sit - this seems to emphasize the need to follow rules more than solve problems. It may seem small - but it is indicative of a larger cultural issue.

[Eldon Tyrell]

I agree with you - there is something culturally odd about the whole thing - foreign feeling.

[Bob]

OK. Watch me "eliminate" the y variable.

Take the first equation. Move the y to the right side and the 5 to the left side (changing signs):

That's a very well written example of solving the problem using the substitution method. The question, however, was asking specifically about using the elimination method. The two methods are fundamentally different in their approaches to solving the problem. While both will work, one or the other may be more easily applied to any particular problem.

[Gene Eric]

I’m guessing the teacher is looking for A.

[Tanniker Smith]

There was a New York State Regents exam a few years back that had a ridiculous question like this. It gave a numerical expression and asked which operation would be the last performed.

What they meant to ask is, "if you were using the Order of Operations, which operation has the least precedence".

The problem was that students with any number sense at all will use the Commutative, Associative and Distributive Properties in their heads without even realizing that they're doing it. In a case like this one (not the aforementioned question, but probably like it):

7^2 + 2 X 5 - 9
you can assume that the student will subtract nine as their final step because it might be obvious upon just reading the question that 2 X 5 - 9 is 1, so that whatever 7 squared is, you just have to add 1 more.

That being said, I just knew they were looking for subtraction, but that doesn't mean it wasn't a stupid question. (I won't speak of "unfair" questions. Just good ones and stupid ones.)