Question

已知xy≠0,且根号(4x^2y^2)=-2xy,则有 √(23-6√(10-4√(3+2√2)))=?

已知xy≠0,且根号（4x^2y^2）=-2xy,则有
A.xy<0 B.xy>0 C.x>0，y>0 D.x<0，y<0

√(23-6√(10-4√(3+2√2)))=?

Answer 1

已知xy≠0,且根号（4x^2y^2）=-2xy,则有
A.xy<0 B.xy>0 C.x>0，y>0 D.x<0，y<0
(1)解析：∵xy≠0,且√(4x^2y^2)=-2xy
√(4x^2y^2)>0==>-2xy>0==>xy<0
∴选择A
√(23-6√(10-4√(3+2√2)))=?
(2)解析：√(23-6√(10-4√(3+2√2)))= √(23-6√(10-4√(1+√2)^2))= √(23-6√(10-4(1+√2)))
= √(23-6√(6-4√2)) = √(23-6√(2-√2)^2) = √(11+6√2) = √(3+√2)^2=3+√2

Answer 2

I DON'T NO