👤

clasa a3-a
afla nr necunoscut:
(18+a)/3=(18/3)+(a/3)
(21-b)/7=(21/7)-(b/7)


Răspuns :

[tex] \frac{a+18}{3}= \frac{18}{3}+ \frac{a}{3}|*3 \\ \\ a+18=a+18 \\ \\ a \in \infty \\ \\ \frac{21-b}{7}= \frac{21}{7}- \frac{b}{7}|*7 \\ \\ 21-b=21-b \\ \\ b \in \infty[/tex]
18+a=18+a (a)
nu depinde de a atunci a∈oricarui nr

21-b=21-b (A)
nu depinde de b atunci b∈oricarui nr