Question

f:Z→Z, f(x)=2x-1
dem ca este injectiva

Answer 1

Poza conține rezolvarea.

Answer 2

f:Z→Z ,a.i. f(x)=2x-1 .

x=y => f(x)=f(y) ,dar f(y)=2y-1 => 2x-1=2y-1 <=> 2x=2y <=> 2·(x-y)=0 <=> x-y=0 <=> x=y => f(x)=f(y) => f(x)=2x-1 este functie injectiva .