Question

Fie functia f:R->R, f(x)=3x-1.
Rezolvați ecuatia 5*f(x+1)=2x+11

Answer 1

[tex]f:\mathbb{R}\rightarrow \mathbb{R}.f(x)=3x-1\\ 5\cdot f(x+1)=2x+11\\ 5\cdot (3x+3-1)=2x+11\\ 15x+10=2x+11\\ 13x=1\Rightarrow \boxed{S:x=\frac{1}{13}}[/tex]

Answer 2

f(x) = 3x-1

Se inlocuieste x cu x+1 in formula de mai sus

f(x+1) = 3(x+1) -1 = 3x+3-1 = 3x+2

Ecuatia din problema devine:

5(3x+2) = 2x+11 ⇔ 15x + 10 = 2x+11 ⇔ 15x-2x = 11-10 ⇔ 13x = 1 ⇔

⇔ x = 1/13 .