Completing the square in a quadratic expression test questions

1

Complete the square on the following quadratic function into the form \({(x + b)^2} + c\):

\[y = {x^2} + 8x + 2\]

2

Complete the square on the following quadratic function into the form \({(x + b)^2} + c\):

\[y = {x^2} + 6x + 15\]

3

Complete the square on the following quadratic function into the form \({(x + b)^2} + c\):

\[y = {x^2} - 8x - 5\]

4

Write \({x^2} + 3x + 1\) in the form \({(x + b)^2} + c\). What's the value of b?

5

The equation \(2{x^2} + 8x - 3 = 0\) is to be solved by completing the square. Which of the following is a correct step in the solution?