Hello there, and thank you for posting your question here on brainly.
Short answer: #1; 5 #2; Explained below
So, we know the answer is 5, so how did I get that? Well, to find that, you have to subtract the two known numbers, 8 and 3. What is 8 - 3? 5. ((8 - 3 = 5))
Hope this helped you! ♥