✔ 最佳答案
x²+2 = x
x²-x+2 = 0
Complete the square:
x²-x+(1/4)+(7/4) = 0
(x - 1/2)² + (√7/2)² = 0
(x - 1/2 - (√7/2)i)(x - 1/2 + (√7/2)i) = 0
x = {1/2 ± (√7/2)i}
You can also use the quadratic formula to get the same answer.
x²-x+2 = 0
ax²+bx+c=0
x = [-b±√(b²-4ac)]/(2a)
a = 1
b = -1
c = 2
x = [1±√((-1)²-4(1)(2))]/2
= [1±√(-7)]/2
= (1±i√7)/2
which agrees with the answer obtained by completing the square