7/(i)
f(x)=3x-6, x aparține lui R
Gf ∩ Ox => f(x)=0
=>3x-6=0
=>3x=6
=>x=2
A(2,0)
Gf ∩ Oy =>x=0
=>f(0)=3*0-6
=>f(0)=-6
B(0,-6)
7/(ii)
(f(x))^2=9 =>
(3x-6)^2=9 =>
9x^2-36x +36=9 /:9 =>
x^2-4x+4-1=0 =>
x^2-4x+3=0 =>
Δ=b^2-4ac
Δ=(-4)^2-4*1*3
Δ=16-12
Δ=4
Δ>0
x1,x2=[-b+/-rad(Δ)]/2a
x1,x2=[-(-4)+/-rad(4)]/2
x1,x2=(4+/-2)/2
x1=(4+2)/2=3
x2=(4-2)/2=1
7/(iii)
f(x)f(x+2)=<0
(3x-6)(3x)=<0
9x^2-18x=<0 /:9
x^2-2x=<0
x^2-2x=0
x(x-2)=0 => x=0
=> x-2=0 => x=2
x^2-2x=<0 => x apartine (0,2)
