Răspuns :
[tex] \frac{9}{3x + 1} = \frac{3}{11} \\ \\ 9 = \frac{3}{11}(3x + 1) \\ \\ 9 = \frac{3(3x + 1)}{11} \\ \\ 9 \times 11 = 3(3x + 1) \\ \\ 99 = 3(3x + 1) \\ \\ \frac{99}{3} = 3x + 1 \\ \\ 33 = 3x + 1 \\ \\ 33 - 1 = 3x \\ \\ 32 = 3x \\ \\ \frac{32}{3} = x \\ \\ x = \frac{32}{3} [/tex]
9/(3x+1) = 3/11
Conditii de existenta 3x+1 != 0 => x != -1/3 (!= inseamna diferit)
Inmultim pe diagonala
99 = 3(3x+1) | :3
3x+1 = 33
3x = 32
x=32/3