(a-15)/(2a^2+6a)+(9-3a^2)/(9-a^2)-3有简要的过程,题目有点烦,计算，算出结果

(a-15)/(2a^2+6a)+(9-3a^2)/(9-a^2)-3有简要的过程,题目有点烦,计算，算出结果
(a-15)/(2a^2+6a)+(9-3a^2)/(9-a^2)-3
有简要的过程,题目有点烦,
计算，算出结果

(a-15)/(2a^2+6a)+(9-3a^2)/(9-a^2)-3有简要的过程,题目有点烦,计算，算出结果
(a-15)/(2a^2+6a)+(9-3a^2)/(9-a^2)-3
=(a-15)/[2a(a+3)]+3(3-a^2)/(3+a)(3-a)-3
=[(a-15)(3-a)+(9-3a^2)(2a)]/[2a(a+3)(3-a)]-3
=(3a-a^2-45+15a+18a-6a^3)/[2a(a+3)(3-a)]-3
=(-6a^3-a^2+36a-45)/[2a(a+3)(3-a)]-3
=(-6a^3-a^2+36a-45-6a(9-a^2)/2a(3+a)(3-a)
=(-6a^3-a^2+36a-45-54a+6a^3)/2a(3+a)(3-a)
=(-a^2-18a-45)/2a(3+a)(3-a)
=-(a+3)(a+15)/2a(3+a)(3-a)
=(a+15)/[2a(a-3)]

(a-15)/(2a^2+6a)+(9-3a^2)/(9-a^2)-3
=(a-15)/[2a(a+3)]+(9-3a^2)/[(3+a)(3-a)]-3
=[(a-15)(3-a)+2a(9-3a^2)]/[2a(3+a)(3-a)]-3
=[-a^2+3a+15a-45+18a-6a^3]/[2a(3+a)(3-a)]-3
=[-6a^3-a^2+36a-45-...

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(a-15)/(2a^2+6a)+(9-3a^2)/(9-a^2)-3
=(a-15)/[2a(a+3)]+(9-3a^2)/[(3+a)(3-a)]-3
=[(a-15)(3-a)+2a(9-3a^2)]/[2a(3+a)(3-a)]-3
=[-a^2+3a+15a-45+18a-6a^3]/[2a(3+a)(3-a)]-3
=[-6a^3-a^2+36a-45-6a(9-a^2)]/[2a(3+a)(3-a)]
=[-6a^3-a^2+36a-45-54a+6a^3]/[2a(3+a)(3-a)]
=(-a^2-18a-45)/[2a(3+a)(3-a)]
=(a^2+18a+45)/[2a(3+a)(a-3)]
=(a-3)(a-15)/[2a(3+a)(a-3)]
=(a-15)/[2a(3+a)]

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题目要求是什么，是分解因式，还是化为一般式？