6.|f(x)|>a (a>0)⇔______________________. 7.|f(x)|g(x)⇔_________________________. 9.|f(x)|<|g(x)|⇔______________. 10.|f(x)|>|g(x)|⇔______________.
f(x)>a或f(x)<-a
-g(x)f(x)>g(x)或f(x)<-g(x)f2(x)f2(x)>g2(x)
f(x)>g(x)或f(x)<-g(x)
f2(x)f2(x)>g2(x)
f2(x)>g2(x)