Question

numarul natural a daca a plus 2 pe 39=7 pe 13 este egal cu.....

Answer 1

(a+2)/39=7/13;a=?
13(a+2)=39*7
13a+26=273
13a=247
a=19

Answer 2

$\frac{a+2}{39} =\frac{7}{13}$
a+2=39·7÷13
a+2=21
a=19