You are Here: Home >< Maths

# C1 Math question. Need help... watch

1. x^2+10x+17
This question is in c1 so you can't use a calculator for this question.
Could anyone talk me through how to solve it?
2. I would complete the square. The mental arithmetic involved should look easier that way than diving straight in with the quadratic formula.
3. I would disagree, every time you see correct your answer to 3 significant figures you have to use the quadratic formula
4. (Original post by kalvin689)
I would disagree, every time you see correct your answer to 3 significant figures you have to use the quadratic formula
Well, the quadratic formula is derived from completing the square, so they are effectively the same thing. But I have to confess that I didn't notice the 3 s.f. bit, which seems worrying for a C1 question, unless it comes out very nicely.
5. Having just had a try, there is no way that this can be done to 3 s.f. without a calculator, unless there is more information at the start of the question that we don't have.
6. (Original post by Pangol)
Well, the quadratic formula is derived from completing the square, so they are effectively the same thing. But I have to confess that I didn't notice the 3 s.f. bit, which seems worrying for a C1 question, unless it comes out very nicely.
Good point, but I believe this is still a very standard and easy C1 question
7. This is all the information provided
10)a) is the question btw

Posted from TSR Mobile
Attached Images

8. (Original post by Vinni0001)
This is all the information provided
10)a) is the question btw

Posted from TSR Mobile
Which textbook is this from?
9. Oops sorry guys, I forgot C1 was non-calc.. It's been a while.
10. I can only assume that you are allowed to use a calculator for this question in the text book, even though you can't in an exam. Perhaps it's adding some extra context, such as when you'll need the same method in C2-C4.
11. Core mathematics 1 edexcel AS and A level modular mathematics from pearsons is the book im using

Posted from TSR Mobile
12. i think at the beginning of the exercise it says only for this exercise you can use the calculator.

I'd still try and get an exact answer from the formula or completing the square regardless, good practise especially the latter. i forget how to do it too often and it helps so often in C3 onwards
13. (Original post by Vinni0001)
Core mathematics 1 edexcel AS and A level modular mathematics from pearsons is the book im using

Posted from TSR Mobile
Ah yes these questions are from the review exercise.

You're meant to use a calculator for these questions. They shouldn't be part of the C1 textbook and you would of course never see a question like this in a C1 exam.
14. Coolio, thanks

Posted from TSR Mobile

### Related university courses

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: October 26, 2016
The home of Results and Clearing

### 1,436

people online now

### 1,567,000

students helped last year
Today on TSR

### University open days

1. Keele University
Sun, 19 Aug '18
2. University of Melbourne
Sun, 19 Aug '18
3. Sheffield Hallam University
Tue, 21 Aug '18
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