The answers are 2. B, 3. D, 4. C, and 5. A.
Step-by-step explanation:
Step 1:
For question 2. 
We subtract both sides by 4 to get

For question 3.
.
We divide the entire equation by 4 to get

Step 2:
For question 4. 
We multiply both sides by 4 to get


For question 5. 
We add 4 to both sides to get


So the answers are 2. B, 3. D, 4. C, and 5. A.
Answer:
10n = d
Step-by-step explanation:
We know that
Each CD is sold for 10 dollars
The music store has sold n amount of CD's
The total number of dollars 'd' depends on how many CD's were sold
The equation is: 10n = d
Hope this helps!
The equation can still be solved but it should be stated clearly at what value of would the equation be undefined. For instance, you have an expression,
1/x+2
When x is equal to -2, the denominator will be 0 resulting to an undefined solution. The value of x here can be any real number except -2.