Х-69=6 и х+41=80 и 80-х=40 и 4+х=15
75-69=6, 39+41=80, 80-40=40, 4+11=15
X-69=6 x=6+69 x=75 x+41=80 x=80-41 x=39 80-x=40 x=80-40 x=40 4+x=15 x=15-4 x=11