To solve this problem you must apply the proccedure shown below:
1. You have the following information given in the problem above:
- x²+y²=74
xy=35
2. Therefore, you have that (x-y)² is:
=(x-y)²
=x²-2xy+y²
=(x²+y²)-2xy
3. When you substitute the values given in the problem, you obtain:
=74-2(35)
=74-70
=4
4. Therefore, as you can see, the correct answer is: 4