1.(-a三次方/x²y)²÷(-x/ay²)三次方×(x/a三次方y)四次方
=a^6/x^4y²×(-a³y^6/x³)×(x^4/a^12y^4)
=-1/a³x³
2.(a²-b²)/a²+b²÷(a²-2ab+b²)²÷(a²+2ab+b²)²/a四次方-b四次方
=(a²-b²)/a²+b²×1/(a-b)^4×(a四次方-b四次方)/(a²+2ab+b²)²
=1/(a²-b²)²
3.(2/-a四次方b三次方)三次方=-8/a^12b^9
4.(-a²y三次方/bx四次方)四次方=(a^8 y^12)/(b^4 x^4)
.(-a²y三次方/bx四次方)四次方=(a^8 y^12)/(b^4 x^4)