Răspuns:
Explicație pas cu pas:
1) a) f:A ----> {4 , 3 , 2 , 1 , 0 , -1} ; f(x) = -x+1
f(x) = 4 => -x+1 = 4 => x = 1-4 => x = -3
f(x) = 3 => -x+1 = 3 => x = 1-3 => x = -2
f(x) = 2 => -x+1 = 2 => x = 1-2 => x = -1
f(x) = 1 => -x+1 = 1 => x = 0
f(x) = 0 => -x+1 = 0 => x = 1
f(x) = -1 => -x+1 = -1 => x = 2
A = {-3 ; -2 ; -1 ; 0 ; 1 ; 2}
b) f: A ---> {0 , 4 , 9 , 16} ; f(x) = x²
f(x) = 0 => x² = 0 => x = ±√0 => x = 0
f(x) = 4 => x² = 4 => x = ±√4 => x = -2 ; x = 2
f(x) = 9 => x² = 9 => x = ±√9 => x = -3 ; x = 3
f(x) = 16 => x² = 16 => x = ±√16 => x = -4 ; x = 4
A = {-4 ; -3 ; -2 ; -1 ; 0 ; 1 ; 2 ; 3 ; 4}
