Solve x
2 - 4x - 7 = 0 by completing the square. What are the solutions?

{2 + , 2 - }
{-2 + , -2 - }
{2 + , 2 + }

Step-by-step explanation:

First, let's move the to the right-hand side so we can determine what constant we'll need on the left-hand side to complete the square:

From here, since the coefficient of the term is , we know the square will be (since it's half of ).

To complete this square, we will need to add to both sides of the equation:

Now we can take the square root of both sides to figure out the solutions to :

b) well because you get well