已知a/b=2/3,则a²-3ab-b²/a²-2ab+b²的值是__________

已知a/b=2/3,则a²-3ab-b²/a²-2ab+b²的值是__________
已知a/b=2/3,则a²-3ab-b²/a²-2ab+b²的值是__________

已知a/b=2/3,则a²-3ab-b²/a²-2ab+b²的值是__________
a/b=2/3
a=2/3b
a²-3ab-b²/a²-2ab+b²
=(2/3b)²-3*2/3b*b-b²/(2/3b)²-2*2/3b*b+b²
=4/9b²-2b²-b²/4/9b²-4/3b²+b²
=(-23/9b²)/(1/9b²)
=-23