(-2×3.14r^2h+3乘以3.14乘rh^2)÷(1/2乘以3.14rh)

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(-2×3.14r^2h+3乘以3.14乘rh^2)÷(1/2乘以3.14rh)

(-2×3.14r^2h+3乘以3.14乘rh^2)÷(1/2乘以3.14rh)
(-2×3.14r^2h+3乘以3.14乘rh^2)÷(1/2乘以3.14rh)

(-2×3.14r^2h+3乘以3.14乘rh^2)÷(1/2乘以3.14rh)
原式=3.14rh(-2r+3h)÷[(1/2)×3.14rh]
=2(-2r+3h)
=6h-4r

即(2x-y)/5=3
(x+y)/3=3
所以2x-y=15 (1)
x+y=9 (2)
(1)+(2)
3x=24
x=8
y=9-x=1
x(a-x)(a-y)^2-y(x-a)(y-a)^2
=x(a-x)(a-y)^2+y(a-x)(a-y)^2
=(a-x)(a-y)^2(x+y)