Question

（2+a-1分之1-a+1分之1）除以（a-1-a平方分之a) 化简

Answer 1

（2+a-1分之1-a+1分之1）除以（a-1-a平方分之a)
=[2+1/(a-1)-1/(a+1)]÷a[1-1/(1-a²)]
=[2+1/(a-1)-1/(a+1)]÷a÷[(1-a²)/(1-a²)-1/(1-a²)]
=[2+1/(a-1)-1/(a+1)]÷a÷[(-a²)/(1-a²)]
=[2+1/(a-1)-1/(a+1)]÷a÷a²/(a²-1)
=[2+1/(a-1)-1/(a+1)]÷a³×(a²-1)
=[2(a²-1)+(a+1)-(a-1)]÷a³
=(2a²-2+a+1-a+1)÷a³
=2a²÷a³
=2/a

追问

x+3分之3=4 解方程
解：4x+12+3=0
4x+15=0
x=4分之15
这样做对吗

追答

错的
4x+12=3
4x=3-12
4x=-9
x=-4分之9

Answer 2

（2+a-1分之1-a+1分之1）除以（a-1-a平方分之a)
=（2+1/(a-1)-1/(a+1)）除以（(a(1-a^2)-a)/(1-a^2))
=（(2(a^2-1)+a+1-a+1)/(a-1)(a+1)）除以（a(1-a^2-1)/(1-a^2))
=（(2a^2-2+2)/(a^2-1)）除以（a(-a^2)/(1-a^2))
=（2a^2/(a^2-1)）除以（a^3)/(a^2-1))
=（2a^2/(a^2-1)）*(a^2-1)/(a^3)
=2/a

追问

（x-1-x-1分之16）÷x²-1分之x+3

追答

（x-1-x-1分之16）÷x²-1分之x+3
=（((x-1)^2-16)/(x-1)）÷ (x+3)/(x²-1)
=（(x-1+4)(x-1-4)/(x-1)）÷ (x+3)/(x²-1)
=（(x+3)(x-5)/(x-1)）* (x+1)(x-1)/(x+3)
=(x-5)(x+1)
=x^2-4x-5