a得平方+b得平方-4a+6b+13=0,
(a-2)^2+(b+3)^2=0,
a=2,b=-3,
所以a^b(a得b次方)=2^(-3)=1/8
x^3-3x^2+3x-9
=x^2(x-3)+3(x-3)
=(x-3)(x^2+3)
能被x+a整除,则a=-3.
a^2+a+1=0,
a^2+a=-1
a^4+a^3-3a^2-4a+3
=a^2(a^2+a)-3a^2-4a+3=-4a^2-4a+3=7.
有知数2^50-4^7能被60到70之间得两个数整除,这两个数是 A.61.63 B.63.65 C.65.67 D.67.69
2^50-4^7=2^50-2^14
=2^14(2^36-1)
=2^14(2^18+1)(2^18-1)
=2^14(2^6+1)(2^12-2^6+1)(2^6-1)(2^12+2^6+1)
2^6+1=65,2^6-1=63.
选(B).
2x^2+2xy+y^2-2x+1=0,
(x+y)^2+(x-1)^2=0,
则x+y=0.