Let's evaluate each question step by step.
Question 1: Evaluate \( 24 - \frac{y}{4} \) when \( y = 12 \).
Substituting \( y \) in the expression:
\[ 24 - \frac{12}{4} = 24 - 3 = 21 \]
The answer is 21.
Question 2: Evaluate the expression \( 2a - 3 + b \) when \( a = 4 \) and \( b = 5 \).
Substituting \( a \) and \( b \) in the expression:
\[ 2(4) - 3 + 5 = 8 - 3 + 5 \]
Calculating it step by step:
\[ 8 - 3 = 5 \] \[ 5 + 5 = 10 \]
The answer is 10.
Final Answers:
- Question 1: 21
- Question 2: 10