The problem asks us to identify which of the given equations have $a=8$ as a solution. We need to choose 3 answers.

1. Problem Description

The problem asks us to identify which of the given equations have $a=8$ as a solution. We need to choose 3 answers.

2. Solution Steps

We need to substitute $a=8$ into each equation and see if it is a valid solution.

A. $a+11 = 15$. Substituting $a=8$, we get $8+11 = 19$. Since $19 \neq 15$, $a=8$ is not a solution.

B. $1 = 8 \div a$. Substituting $a=8$, we get $1 = 8 \div 8 = 1$. Since $1=1$, $a=8$ is a solution.

C. $15+a = 23$. Substituting $a=8$, we get $15+8 = 23$. Since $23=23$, $a=8$ is a solution.

D. $42 = 7a$. Substituting $a=8$, we get $42 = 7 \times 8 = 56$. Since $42 \neq 56$, $a=8$ is not a solution.

E. $a-5 = 3$. Substituting $a=8$, we get $8-5 = 3$. Since $3=3$, $a=8$ is a solution.

3. Final Answer

B, C, E