Question

X2-X-1=0 怎么计算X2 是X的平方

Answer 1

（X2-X+1/4-1/4)-1=0

(X-1/2)2-5/4=0

(X-1/2)2=5/4

X-1/2=（根号5）/2 X-1/2=-（根号5）/2

X=1/2+（根号5）/2 或 X=1/2-（根号5）/2