19x-8x=55 2×(7x-4x)=18 6x+8x=1.4×3 5x+0.1x=50+6.1 7.2x-3.6x=9×0.4 20=5x-3X.

问题描述:

19x-8x=55 2×(7x-4x)=18 6x+8x=1.4×3
5x+0.1x=50+6.1 7.2x-3.6x=9×0.4 20=5x-3X.

(1)19x-8x=55,            11x=55,        11x÷11=55÷11,        &n...