2. f(x)=8 => x+1 = 8 => x=7
3. f(x)>=1 => x+4>=1 => x>=-3 => x€[-3, infinit)
4. f(2) = 2-3 = -1
f(5) = 5-3 = 2
=> m_a = (f(5)+f(2))/2 = (2-1)/2 = 1/2
5. Gf intersectat cu Oy => x=0 =>
f(0) = 3*0-1 = -1 => A(0,-1)
6. Gf intersectat cu Ox => f(x)=y, y=0 => 2x-4 = 0
2x = 4
x = 2 => B(2,0)