What number is needed to complete the square x2-23x equals 0?

Answer 1

(23/2)2

x2 - 23x = 0

x2 - 23x + (23/2)2 = (23/2)2

(x - 23/2)2 = (23/2)2

x - 23/2 = 23/2

x = 23/2 + 23/2

x = 23

Of course you could come to this solution much more easily by dividing the whole equation by x at the start. There really is no need to complete the square in this case:

x2 - 23x = 0

x - 23 = 0

x = 23