Odpowiedzi

2009-04-20T21:19:34+02:00
A)f(x)=3/(5x+12)
5x+12≠0
5x≠-12
x≠-12/5
x≠-2⅖ D: x∈R\{-2⅖}

b)f(x)= 7/(x²+9) D:x∈R

c)f(x)= -3/(x²-4)
x²≠4
x≠2 i x≠-2
D: x∈R\{-2, 2 }

d) f(x)=x²+25 D: x∈R