Ответ:\(-2x+3x-4x=-3x\).\(0.2x-4x-\frac15y=-3.8x-0.2y\).\(\frac29x-2x+\frac79y=-\frac{16}{9}x+\frac79y\).\(3x-\frac25x-0.6x=2x\).\(\frac12x+x+\frac12x-x=x\).\(-\frac45x-0.2x-x=-2x\).