posted by Keisha (for drwls) .
The question is on sets not solving for a straight line, the info on A is in one circle and B in the other circle, X is the intersection between both circles and i still don't have the working, even though i know the ans is 9 i need the working to be sure i did it correctly.
Dr WLS gave you the answer but I will elaborate:
The answer is in both set A and in set B since it is the intersection.
Therefore the question is: Where is 3x-4 also 2x+5.
To find out for what x this is true, set them equal.
3x-2x = 5+4
x = 9