Solving Quadratic Equations using the Square Root Property

but the teacher's guide says the answer is 17i

  or  

Step-by-step explanation:

You need to complete the square before you can take the square root of both sides.

Subtract 10 from both sides.

To complete the square, you need to add the square of half of the x-term coefficient to both sides.

The x-term coefficient is 7. Half of that is 7/2. Square it to get 49/4. Now we add 49/4 to both sides of the equation.

Now we use the square root property, if

, then

  or  

  or  

  or