rezolvati in multimea nr. naturale ecuatia :
3×{10+2×[40-2×(28-3×5)]}-7x=51


Răspuns :

3X{10+2X[40-2X(28-15)]}-7X=51
3X[10+2x(40-2x13)]-7x=51
3x[10+2x(40-26)]-7x=51
3x(10+2x14)-7x=51
3x(10+28)-7x=51
3x38-7x=51
114-7x=51
7x=114-51
7x=63
x=63:7
x=9