Question

La fiecare dintre cerințele de mai jos, analizați variantele de răspuns A-E și indicaţi-le pe cele
corecte. Atenție! Pot exista mai multe variante corecte, una singură sau nicio variantă corectă.

Answer 1

• Ca un punct A(x,y) sa apartina unui Gf ⇒ f(x)=y

a. f(x)=-x+1

A(-1,2)

f(-1)=1+1=2⇒ A∈Gf

B(2,3)

f(2)=-2+1=-1⇒ B∉Gf

C(5,-1)

f(5)=-5+1=-4 ⇒ C∉Gf

D(4,-3)

f(4)=-4+3=-1⇒ D∈Gf

E(3,3)

f(3)=-3+1=-2⇒ E∉Gf

b.f(x)=-2x+6

A(3,0)

f(3)=-6+6=0⇒A∈Gf

B(1,-4)

f(1)=-2+6=4⇒ B∉Gf

C(-2,10)

f(-2)=4+6=10⇒C∈Gf

D(-1,4)

f(-1)=2+6=8⇒D∉Gf

E(2,2)

f(2)=-4+6=2⇒ E∈Gf

c. f(x)=-4x+11

$A(\frac{1}{2},8)\\\\ f(\frac{1}{2})=-2+11=9$⇒ A∉Gf

$B(\frac{11}{4} ,0)\\\\f(\frac{11}{4})=-11+11=0$⇒B∈Gf

$C(-\frac{3}{4} ,6)\\\\f(-\frac{3}{4} )=3+11=14$ ⇒C∉Gf

$D(\frac{7}{3} ,\frac{5}{3} )\\\\f(\frac{7}{3} )=-\frac{28}{3} +11=\frac{5}{3}$⇒D∈Gf

$E(\frac{11}{5} ,\frac{11}{5})\\\\f(\frac{11}{5})=-\frac{44}{5} +11=\frac{11}{5}$⇒E∈Gf

d.f(x)=3x-1

A(0,-1)

f(0)=0-1=-1⇒ A∈Gf

B(-1,4)

f(-1)=-3-1=-4⇒B∉Gf

$C(\frac{1}{3},0) \\\\f(\frac{1}{3})=1-1=0$⇒C∈Gf

$D(\frac{2}{9},\frac{1}{3})\\\\ f(\frac{2}{9} )=\frac{2}{3}-1=-\frac{1}{3}$⇒ D∉Gf

$E(\frac{1}{2} ,\frac{1}{2})\\\\f(\frac{1}{2})=\frac{3}{2} -1=\frac{1}{2}$⇒E∈Gf