Question

Algebra: Changing the subject

Answer 1

Your answer and the correct answer are essentially the same.

In the correct answer the top and bottom has been multiplied by -1. The top changes from (-w-x) to (w+x), and bottom changes from (w-x) to (-x+w) which is (w-x)

Answer 2

Your answer is right. There's no "wrong" order. I probably would have done what they did just because fewer negatives feels like less clutter. What *does* matter is using ()'s when typing because fractions become ambiguous.

Answer 3

>m = -wn-xn/w-x

Your answer is correct, but should be formatted as

m=(-wn-xn)/(w-x).

"They" factored out a negative n to give

-n(w+x)/(w-x)

and then multiplied numerator and denominator by negative 1

Your answer is also correct but might be marked wrong by an input form

Answer 4

I would have moved m to the other side to have more positive numbers than negatives (which

1) wm + wn = xm - xn

2) xn + wn = xm - wm

3) n (x + w) = m (x - w)

4) [n (x + w)]/(x - w) = m

which is the same as

5) m = [n (x + w)]/(x - w)

Now for your problem with orders, x-w is not the same as w-x, 4-3= 1 is not the same as 3-4= -1

You can see in line 2 i put first xn and then wn even though wn was on that side in the first place, in this case it doesn matter because you're adding numbers, wn + xn is the same as xn + wn. Same with -wn - xn, you're adding negative numbers, it's still addition. The problems come when subtracting numbers (essentially adding negative and positive numbers together, in this case the order does matter)

In step 2 you did what you're supposed to do. wn was on that side first so you put it first, then you put -xm