急! 急! 急! F4 數

put x - √ 6 i = -1 + √ 6 i∴ x = -1 + 2√ 6 i put x - √ 6 i = -1 - √ 6 i∴ x = -1

2011-11-01 17:15:20 補充：
-1 + √ 6 i and -1 - √ 6 i are the roots of the equation x^2 + 2x +7 = 0
it means
(-1 + √ 6 i)^2 + 2 (-1 + √ 6 i) + 7 = 0
(-1 - √ 6 i)^2 + 2 (-1 - √ 6 i) + 7 = 0

上面D嘢唔洗寫
Hence solve (x - √ 6 i )^2 + 2(x - √ 6 i ) + 7 = 0

∴ x - √ 6 i = -1 + √ 6 i

or x - √ 6 i = -1 - √ 6 i