Question

a-2分之4÷（a-4a+4分之a²-a-2 - a-2分之1 + 1）

如题，求速度。5分钟

Answer 1

断句
真难！大概是：
4/(a-2)÷{(a^2-a-2)/[(a-4)(a+4)]-1/(a-2)+1}
=4/(a-2)÷[(a-2)(a^2-a-2)-(a-4)(a+4)+(a-2)(a-4)(a+4)]/[
(a-2)
(a-4)(a+4)
]
=4/(a-2)÷(a^3-a^2-2a-2a^2+2a+4-a^2+16+a^3-16a-2a^2+32)/[
(a-2)
(a-4)(a+4)
]
=4/(a-2)÷(2a^3
-6a^2-16a+52)/[
(a-2)
(a-4)(a+4)
]
=2(a-4)(a+4)/(a^3
-3a^2-8a+26)
=2(a^2-16)/(a^3-3a^2-8a+26)