Let's solve the equations step by step:

1. $1 + 4 = 5$

2. $9 - 2 \times 3 = 9 - 6 = 3$
   (Remember, multiplication comes before subtraction due to the order of operations or PEMDAS/BODMAS rule).

3. $(7 - 5) \times (3 + 1) = 2 \times 4 = 8$
   (Solve the expressions inside the parentheses first, then multiply).

Final answers:

1. $1 + 4 = 5$
2. $9 - 2 \times 3 = 3$
3. $(7 - 5) \times (3 + 1) = 8$

Would you like further details or explanations?

Here are 5 related questions to expand your understanding:

1. What is the order of operations in mathematics?
2. How do parentheses affect the outcome of an equation?
3. Can you solve $10 + 2 \times (6 - 4)$?
4. What happens if there are multiple multiplication and division operations?
5. How would you simplify $(8 - 3) + 4 \times 2$?

Tip: Always remember the order of operations: Parentheses, Exponents, Multiplication/Division (from left to right), Addition/Subtraction (from left to right).