daca x/y = 2/5 atunci:
a). 3x / y = 3 * (x/y) = 3* (2/5) = 6/5 ;
b). x / 5y =(x/y) : 5 = (2/5) :5 = 2/5 * 1/5 = 2/25 ;
c). (1/3 )x / (1/2) y = x/3 : y/2 = x/3 * 2/y = (x/y)*(2/3)=2/5*2/3=4/15 ;
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↑
daca avem (1/3)*x si (1/2)*y
d). y²/x² = (y/x)² = (5/2)² = 25/4 ;