1.3y²分之2x²×6x分之5y÷21x的平方分之10y
=(3y² × 6x ×10y)分之(2x² × 5y × 21x²)
=6y²分之7x³
2.9-x²分之x²-6x+9÷x²+3x分之2x-6
=(3+x)(3-x)分之(x-3)² × 2(x-3)分之x(x+3)
=-x/2
3.2ab分之4a²+4ab+b²×6a+3b分之2a²b.
=2ab分之(2a+b)² × 3(2a+b)分之2a²b
=a(2a+b)/3
=(2a²+ab)/3
4已知X-3Y=0,求x²-2xy+y²分之2x+y ×（x-y)
X-3Y=0
则,x=3y
x²-2xy+y²分之2x+y ×（x-y)
=(x-y)² 分之 (2x+y)(x-y)
=(x-y)分之 (2x+y)
=(3y-y)分之 (6y+y)
=2y分之7y
=2分之7