(1)15x³y5次方(y-x)³分之12x²y(x-y)4次方
=12x²y(y-x)^4/15x³y^5(y-x)³
=4x^(-1)y^(-4)(y-x)/5
(2)4x²-4分之1-2x+x²
=(x-1)²/4(x+1)(x-1)
=(x-1)/4(x+1)
(3)x²+10x-24分之2x²-2x-4
=2(x²-x-2)/(x²+10x-24)
=2(x-2)(x+1)/(x-2)(x+10)
=2(x+1)/(x+10)
（4）解答题：已知x-3y+4=0,
x-3y=-4
分式2x+4y分之x²-xy-6y²
=(x-3y)(x+2y)/2(x+2y)
=(x-3y)/2
=-4/2
=-2
（5）填空a-1=a+3分之（a^2+2a-3 ）
（6）填空2x-1分之2x=2x²-x分之( 2x² )
(7)填空x²-xy-2y²分之2x²+4xy+2y²=( x-2y )分之2（x+y)
(8)填空9x²-6xy+y²分之3x²-xy=( 3x-y )分之x=9x²-y²分之（ 3x^2+xy )