Question

Fie functia f: R--R,f(x)=2x+3 a) calculati f(f(-1)),f(f(2)) b)pentru care valori ale lui x obtinem f(x)=f(f(x))

Answer 1

a)■ f○f(x)=2(2x+3)+3=4x+6+3 => f(f(-1))= 4×(-1)+9=5 ■ f(f(2))=4×2+9=17 ■b) 2x+3=4x+9 => -2x=6 => x=6 :(-3)= -2