Răspuns :
x- 3/7×x- 2/5×x = 720
35×x - 35× 3/7 ×x- 35× 2/5× x =35× 720
35x - 5×3x - 7×2 x = 25200
35x-15x -14x = 25200
6x = 25200
x= 25200:6
x= 4200
35×x - 35× 3/7 ×x- 35× 2/5× x =35× 720
35x - 5×3x - 7×2 x = 25200
35x-15x -14x = 25200
6x = 25200
x= 25200:6
x= 4200
[tex] \frac{3}{7} \times 750 = \frac{3 }{7} \times \frac{750}{1} = \frac{2250}{7} [/tex]
[tex] \frac{2250}{7} \times \frac{2}{5} = \frac{4500}{35} = 128.571[/tex]