Question

Which perfect square equation represents x^2+4x+1=0 by completing the square?
A . (x+2)^2=3
B. (x+4)^2=-3
C. (x+2)^2=-1
D. (X+2)^2=5

Answer 1

First thing to do is to move the constant over to the other side of the equals sign.  Then we will complete the square on the x terms.  We will take half the linear term, square it, then add it to both sides.  Our linear term is 4.  Half of 4 is 2, and 2 squared is 4. $x^2+4x+4=-1+4$.  In the process of completing the square we have created a perfect square binomial on the left which is $(x+2)^2=3$.  A is our answer.