For Question 3 regarding the equation \( 5x + 1 = 5x + 4 \):
- The student's final simplification results in \( 1 = 4 \), which is a false statement.
- Since the student arrived at a contradiction (a false statement), we can conclude that the original equation has no solutions.
Therefore, the correct conclusion is:
- This equation has no solution.
For Question 4 regarding the equation \( 3(x + 1) = 3x + 4 - 1 \):
- The statement that the left side is identical to the right side implies that the two expressions are equal for all values of \( x \).
- When two expressions are identical for all values of \( x \), it indicates that there are infinitely many solutions.
Therefore, the correct conclusion is:
- This equation has infinitely many solutions.
In summary:
- For Question 3: "This equation has no solution."
- For Question 4: "This equation has infinitely many solutions."