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# Make a the subject watch

1. ab = 1-a
2. (Original post by AlevelMaths42)
ab = 1-a
If you bring a to the other side, then you should be able to factor it out, and go from there
3. (Original post by solC)
If you bring a to the other side, then you should be able to factor it out, and go from there
I got a = 1/2b Is that right?
4. (Original post by AlevelMaths42)
I got a = 1/2b Is that right?
No that doesn't seem right. How did you get to that answer?
5. (Original post by solC)
No that doesn't seem right. How did you get to that answer?
ab = 1-a +a
2ab = 1 /b
2a=1/b /2
a=1/2b
6. (Original post by AlevelMaths42)
ab = 1-a +a
2ab = 1 /b
2a=1/b /2
a=1/2b
You cannot add ab and a since they are not the same thing. What you need to do is take a factor of a out of the whole thing, like a(1+b).
7. (Original post by solC)
You cannot add ab and a since they are not the same thing. What you need to do is take a factor of a out of the whole thing, like a(1+b).
I've tried it again and got a = 1-2b / 2
More like it? or still wrong?
8. hey man, what you did was completely wrong, instead of trying to do it via trial and error perhaps go to the chapter this is located and try and do the easier question
ab = 1-a
ab+a=1
a(b+1)=1
a=1/(b+1)

EDIT - you could always just drop maths
9. (Original post by AlevelMaths42)
I've tried it again and got a = 1-2b / 2
More like it? or still wrong?
ab = 1-a +a
2(ab) = 1
expand
2a+2b=1 -2b
2a=1-2b /2
a= 1-2b/2
10. (Original post by AlevelMaths42)
ab = 1-a +a
2(ab) = 1
expand
2a+2b=1 -2b
2a=1-2b /2
a= 1-2b/2
Like i said previously, a+ab is not 2ab and even if it were, expanding it does not give what you stated. If it were 2(a+b) then you would be correct but its only a single term of ab. Perhaps you should have a read over the rules for factorising and expanding brackets before coming back to this question
11. (Original post by zainyyyyy)
hey man, what you did was completely wrong, instead of trying to do it via trial and error perhaps go to the chapter this is located and try and do the easier question
ab = 1-a
ab+a=1
a(b+1)=1
a=1/(b+1)

EDIT - you could always just drop maths
GCSE - name is bros account - I'm 12

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