List of the first few prime numbers greater than 3:
5, 7, 11, 13, 17, 19, 23, 29
Now find the combination that you can multiply and still have a 2 digit number:
5 x 7 = 35
5 x 11 = 55
5 x 13 = 65
5 x 17 = 85
5 x 19 = 95
5 x 23 = 115 ( 3 digit number, can't use).
7 x 5 = 35
7 x 11 = 77
7 x 13 = 91
7 x 19 = 133 ( 3 digit number, can't use).
The largest 2 digit number would be 5 x 19 = 95
I don't have my calculator handy just now. But just looking at that problem, why don't you try +20 and -45 and see if they do the job.
I believe it is 864, I'm not 100% sure. But I think it is.
When x is -1 Y will equal -1
