Упростить 3 6/7x-7/9x+4 4/63
3 6/7x = x * 3 6/7 ? Или так: 3 6/7x = 3 6/(7x) ?
3 6/7х -7/9х+ 4 4/63=(3 6/7-7/9+4 4/63)х=(3 54/63-63/49+4 4/63)х=7 1/7х