1.

You can use the quadratic here, or complete the square and solve. Using quadratic:

2.

You are half right; though the "Bx" isn't visible, it is there. Your B, as with your C in question one, is 0, therefore the term drops off. I could just as easily write this as:

Or we could use: "-Solve using the square root method"

A.

Using the quadratic:

- Set up our quadratic.

- Perform operations.

- Factor a 4 out of the quantity under the square root sign.

- Take the square root of 4, and bring it out of the square root sign.

- Dive by 2.

All of the problems you have can be solved using all off the methods you outlined in your problem - it is just easier to use one method over another. For example:

Can be solved using the quadratic, or much quicker to use the "square root method" as I mentioned. Your task is figuring out which is the easiest way to go about solving.

To check that you understand how to do these problems, use multiple methods to solve the same problem.