# Triangles and algebra A-level maths

#1
I have this question on a homework where we are given a triangle labelled A, B and C

angle A= 120 degrees
length AB =x-1
length BC =x+1
length AC =2x1

I am meant to find the value of x

I have tried working it out by using the cosine rule, however, my equation turned out to have no real roots so I do not know where I went wrong. Any help?
0
3 months ago
#2
Sounds like youve tried to do the right thing. Upload your working pls.
1
3 months ago
#3
I have tried the problem using:

or

In one case I also got complex roots, in the other case I get two real numbers but both could lead to negative distances.

It is possible I may have made an algebraic mistake or misunderstood the question as well.

As above, it would help if you showed your working out and also upload the question in its original format.
0
3 months ago
#4
(Original post by 0le)
I have tried the problem using:

or

In one case I also got complex roots, in the other case I get two real numbers but both could lead to negative distances.

It is possible I may have made an algebraic mistake or misunderstood the question as well.

As above, it would help if you showed your working out and also upload the question in its original format.
Agreed. The first option isnt a triangle as its bigger than the sum of teh other two sides but its not clear in the question. I was hoping they would upload something.
0
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