#### Sassbean19

##### New member

- Joined
- Nov 6, 2019

- Messages
- 2

But the fundamentals are still eluding me (maths is not my strong point to say the least).

How do I know which operations to perform to get the right answer, since it seems I could trial and error several answers for each equation which are not correct.

For example, I am struggling with the following:

Rearrange the following to make x the subject:

y=7-2x

So where am I "supposed" to start?

I have tried dividing by x first, but this leads to a seemingly dead and incorrect end (unless I'm missing something?). = y/x = 7-2

Then I tried dividing by 7 first leaving

y/7 = -2x

then multiplying by -2 to give: y/(7-2) but then I don't know if its actually (y-2)/7 = x because I don't know a rule to say whether the multiplied number moves to the top or bottom of the division on the other side, or essentially brackets the division as its own operation and acts on the whole thing: (y/7)-2 etc.

Anyway, it doesn't matter because all the above are incorrect...

I have been given the answer by the system, the above is just examples of how I am approaching this, since it worked for me in simpler questions..

The given answer is:

x = (7 - y)/2

brackets are just to show 7 - y as being on the top half of the division line..

I have no idea how to get to the answer.. like there must be a process to lead to it that is based in something other than trial and error with operations, right? Otherwise how do you ever know you're correct? What am I missing this is driving me crazy...

Thanks all