Respuesta :

25 -4x = 15 - 3x + 10 - x     combine x terms on the left side:
25 - 4x + 3x + x = 15 + 10 - 25    and constants on the right side

25 = 10    this can never be true, so there is no solution.  Ensure that you have copied down this problem correctly.
-4x=15-3x+10-x
-4x-3x=-7x
-7x=15+10-x
-7x=25-x
-8x=25