1. Solve the following equations for $x$. Write your answer in set notation. a. $3 x-5=16$

Step 1 ：Add 5 to both sides of the equation to get rid of the -5 on the left side. This will give us \(3x = 21\).

Step 2 ：Divide both sides by 3 to solve for \(x\).

Step 3 ：The solution to the equation is \(x = 7\). This is the only solution, so the set of solutions is \(\{7\}\).

Step 4 ：Final Answer: \(\boxed{\{7\}\})