Question

若a=三分之二,则（分数）a平方-7a+12分之a平方-2a-3的值等于,

Answer 1

(a²-2a-3)/(a²-7a+12)

=(a-3)(a+1)/(a-3)/(a-4)

=(a+1)/(a-4)

=(2/3+1)/(2/3-4)

=5/3/(-10/3)

=5/3*(-3/10)

=-1/2