Răspunsuri

2014-10-04T19:43:00+03:00
X÷21=c+15
x=21c+15
cazul 1 :c=1 atunci x=21+15=36

36÷3=12 rest 0
36÷6=6 rest 0
cazul 2: c=2 atunci x=21×2+15=42+15=57
57÷3=19 rest 0
57÷6=9 rest 3
cazul 3 :c=3 si tot asa pana la c=9