How do you solve #x^2 + 2x = 3# by completing the square?

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How do you solve #x^2 + 2x = 3# by completing the square?

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Answer 1 · 2016-05-26T21:23:52

#x = 1# or # x = -3#

Explanation:

In #x^2 + 2x# a third term is missing to be able to write the square of a binomial.
Find it by dividing the coefficient of #x# by 2, square it and add to both sides.

#x^2 + 2x + color(red)1 = 3 + color(red)1 #

#(x + 1)^2 = 4#

#x + 1 = +-sqrt4 = +-2#

#x = +2 - 1# or # x = -2-1#

#x = 1# or # x = -3#

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How do you solve #x^2 + 2x = 3# by completing the square?

1 Answer

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