3(7+2k) - 4( -7 + 1/2 k)= - 19 6
3(7+2k) - 4( -7 + 1/2 k)= - 196 21+6K+28-2K=-196 4K=-196-21-28 4K=-245 K=-61целая 1/4 k=-61,25
21+6k+28-2k=169 4k=120 k=30