a=-(1/2),b=2
(-1/2)*2
=(-1/2)^2-2[3*(-1/2)-1/2]÷(-1/2-2)
=1/4-2(-3/2-1/2)÷(-1/2-2)
=1/4-2*(-2)÷(-5/2)
=1/4-8/5
= -27/20
他输入的a=2,使得a-b=0了,分母不能为零.
a=-(1/2),b=2
(-1/2)*2
=(-1/2)^2-2[3*(-1/2)-1/2]÷(-1/2-2)
=1/4-2(-3/2-1/2)÷(-1/2-2)
=1/4-2*(-2)÷(-5/2)
=1/4-8/5
= -27/20
他输入的a=2,使得a-b=0了,分母不能为零.