You are Here: Home >< Maths

# Question on C4 Marking Watch

1. Hello, I was doing a Solomon Press Paper for C4 a few minutes ago and I stumbled upon a question asking me to find the inverse function. [The question is below]

f(x)= (2x-1)/(x-1)
For the inverse function I got (1-x)/(2-x) whereas the marking criteria says the answer is (x-1)/(x-2).

Would this be a problem in the actual exam or is it fine?

2. (Original post by RSharma98)
Hello, I was doing a Solomon Press Paper for C4 a few minutes ago and I stumbled upon a question asking me to find the inverse function. [The question is below]

f(x)= (2x-1)/(x-1)
For the inverse function I got (1-x)/(2-x) whereas the marking criteria says the answer is (x-1)/(x-2).

Would this be a problem in the actual exam or is it fine?

They're identical so it's fine.
3. It's the same answer because if you think about it, just sub in any number for x, so for example x=5

Using your answer you'd get - 4/-3, which is ultimately 4/3. If you used their answer, you'd get to 4/3 straight away. So either way it is correct

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: June 18, 2016
Today on TSR

### Last-minute PS help

100s of personal statements examples here

### Loneliness at uni

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.