Răspuns:
a/b=1,(5)
a/b=(15-1)/9=14/9=>a=14b/9
(2a-3b)/2b=[(2·14b)/9-3b]/2b=(28b/9-⁹⁾3b)/2b=b/9:2b=b/9·1/2b=b/18b=1/18
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(a+2b)/3b=[(14b/9+⁹⁾2b)]/3b=[(14b/9+18b/9)]/3b=32b/9:3b=32b/9·1/3b=32b/27b=32/27
