Question

Find two numbers whose product is 42 and difference is 1.

Answer 1

Okay, So We Need Two Numbers That Multiply To Get 42. Lets Look At All Of The Ways To Get 42.
1 * 42 
2 * 21
6 * 7
7 * 6 
21 * 2
42 * 1

So, 21 and 2 don't have a difference of one. 
42 and 1 don't have a difference of one. 

6 and 7 have a difference of one, which means your two mystery numbers are 6 and 7.