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# help with 2 c3 qs watch

1. https://b3755649dbd1afe3db91a899c3b9...%20Edexcel.pdf

Q7c) Why can't I have 1 MINUS root x-4 ?

Q4b)
I got the answer, however, I used trial and error...
Mark scheme does it algebraically:
-1 = a+b
-5 = a-b
Why does the first equation have a +
and the second equation has a -
2. (Original post by ps1265A)
https://b3755649dbd1afe3db91a899c3b9...%20Edexcel.pdf

Q7c) Why can't I have 1 MINUS root x-4 ?

Q4b)
I got the answer, however, I used trial and error...
Mark scheme does it algebraically:
-1 = a+b
-5 = a-b
Why does the first equation have a +
and the second equation has a -
7c Because for the inverse function to exist, f(x) must be one-to-one so can only have one value

4b

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