a,b互为相反数,即a+b=0
c,d互为倒数,即cd=1
x的绝对值是1,即X=(+/-)1
X^2=1
a+b+x的二次方-cdx
=0+1-1*X
=1-X
(1)X=1时,原式=0
(2)X=-1时,原式=2