Răspuns:
x-12,5=13si1/5
x-12,5=66/5
x-125/10=66/5
x=66/5+125/10
x=132/10+125/10=257/10=25,7
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x+14,31-54=-3/5
x+1431/100-5400/100=-60/100
x=-60/100-1431/100+5400/100
x=3909/100=39,09
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4/3:x=5/3-4/3
x=4/3:1/3
x=4/3·3/1=4
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1,(3)=(13-1)/9=12/9=4/3