Răspunsuri

2014-07-20T16:10:51+03:00
X:9=c-1 rest c

x=9(c-1)+c

x=9c-1+c

x=10c-1

x=M₁₀ -1

x=10*1-1=10-1=9
x=10*2-1=20-1=19
x=10*3-1=30-1=29
x=10*4-1=40-1=39
x*10*5-1=50-1=49
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