Odpowiedź:
1/3x + x =120
[tex]1\frac{1}{3} x\\[/tex] = 120 / :[tex]1\frac{1}{3} \\[/tex]
x = 90
ps. daj naj
[tex]\frac{1}{3}x + x = 120 \ \ /\cdot3\\\\x + 3x = 360\\\\4x = 360 \ \ /:4\\\\\boxed{x = 90}[/tex]
