Question

整式的乘法 6题~1.x^2-y^2-x+y=(x-y)A,则A=_______.2.已知2^x=3,2^y=5,2^z

Answer 1

1.x^2-y^2-x+y =(x+y)(x-y)-(x-y) =(x-y)(x+y-1) 所以A=x+y-1

2.(2^x)*(2^y)=15,同时(2^x)*(2^y)=2^(x+y)=15,所以 x+y=z.

3.5^23-5^21=5^21（5^2-1）=（5^21）*24,因为5*24=120,所以能被120整除

4.m^2+m-1=0 则m^2+m=1

m^3+2m^2-2004=m^3+m^2+m^2+2004 =m(m^2+m)+m^2+2004

=m^2+m+2004 =1+2004 =2005

5.4^x*32^y=2^2x*2^5y =2^(2x+5y) =2^3 =8

6.3x(x^n+5）=（3x^n+1）+15x=（3x^n+1）-7,所以x=-7/15.

---------西南石油大学 我的精灵英格玛