x^2-13x+21 = 0
x^2-13x+(13/2)^2 + 21 - (13/2)^2 = 0
(x - 13/2)^2 - 85/4 = 0
x - 13/2)^2 = 85/4
x - 13/2 = ±√85/2
x = (13±√85)/2
solve the following equation by completing the square
x(square) -13x + 21 = 0
Then x= or x=
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