3x³y³*(-2/3x²y)³+(-1/3x²y)³*9xy²
=3x³y³(-8/27)x^6y³-(9/27)x^6y³xy²
=-8/9x^9y^6-(1/3)x^7y^5
=-8/9(-1)^9(2^6)-(1/3)(-1)^7(2^5)
=(8/9)64+32/3
=64*8/9+96/9
=512/9+96/9
=608/9确定吗确定