整式的整除．很简单拉．1.已知5^m=35^n=3则有5＾m-2n=,5^2m+n=.2.已知x-y=3.xy=2则x+y=.3.((-2a^3x^2)(a-2x)-0.75a^2x^2)/(-(ax)^2)要过程哦．是平方还是乘2要写清楚噶．．．谢谢．条理不系很清楚诶．．

Question

整式的整除．很简单拉．
1.已知5^m=3 5^n=3 则有5＾m-2n= ,5^2m+n= .
2.已知x-y=3 .xy=2 则x+y= .
3.((-2a^3 x^2)(a-2x)-0.75a^2 x^2)/(-(ax)^2)
要过程哦．是平方还是乘2要写清楚噶．．．谢谢．
条理不系很清楚诶．．．=±√17

Answer 1

5＾m-2n=(5^m)/(5^n)^2=3/(3^2)=1/3
x-y=3两边平方得
x^2-2xy+y^2=9
加上4xy得
x^2+2xy+y^2=17
所以(x+y)^2=17
x+y=±√17
((-2a^3 x^2)(a-2x)-0.75a^2 x^2)/(-(ax)^2) =-a(16ax-8a2-3)/4
±√17是17的两个平方根