Question

已知a与b互为相反数,c与d互为倒数，x=3（a-1)-(a-2b),y=c2d+d2-(d/c+c-2),求2x-y/3-3x+2y/6的值

已知a与b互为相反数,c与d互为倒数，x=3（a-1)-(a-2b),y=c2d+d2-(d/c+c-2),求2x-y/3-3x+2y/6的值紧急

Answer 1

化简
x= -(a-2b)-3(1-a)
=-a+2b-3+3a
=2b+2a-3
=2(a+b)-3 a和b互为相反数 所以和为0
=2*0-3
=-3
x=-3

y=c2d+d2-[(d/c) +c-1]
=(c^2)d+d^2-(d/c)-c+1
=c(cd)+d^2-d^2-c+1 c和d互为倒数 积为1 d/c=d乘c的倒数 也就是d 所以为d^2
=c-c+1
=1

x=-3 y=1代入式子 得
(-6+1/3)-(-9-1/3)
=3+2/3
=11/3

Answer 2

-3