原式=ab-2b-2a+4
=ab-2a-2b+4
=ab-2(a+b)+4
带入得,3/2-2×1+4=7/2
(a-2)(b-2)
=ab-2(a+b)+4,
当a+b=3/2,ab=1时,
原式=1-2×3/2+4=2.
(a-2)(b-2)
=ab+2(a+b)-4
=1+3-4
=0
祝学习进步
(a-2)(b-2)
=ab-2a-2b+4
=ab-[2(a+b)]+4
因为a+b=3/2,ab=1
所以上式=1-[2x3/2]-4
=1-3-4
=-6
(a-2)(b-2)
=ab-2(a+b)+4
=1-3+4
=2