13х+4х=408 7в+6в=403 47х-15х=2144
13х+4х=408 17х=408 х=408:17 х=24 7в+6в=403 13в=403 в=403:13 в=31 47х-15х=2144 32х=2144 х=2144:32 х=67
X=9 x =4 b=9 b=6 x=3 x=2