PrepSwift Completing the Square Exercise Question 3

GRE Quant Problem Solving
1

I don’t understand the solution here. In the PrepSwift Video we learn that we have to set the equation to zero, but this solution doesn’t do it?

After completing the square, I end up with (x+2)'2 -1=0.

So I chose -3. X has to be either -1 or -3 in order for the LHS to be equal to zero.

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2

What are you supposed to find actually (hint: it’s not the root)?

3

The minimum value of the expression

4

Correct, and what do you think is happening if you try setting the equation to 0?