Question

Determinati nr nat x din :

a) $2^{x}$ -4=4

b)$[(5*2*7) ^ {2}$ +x] - 401=5*10²

Answer 1

a)2^x-4=4=>2^x=8=>x=3;;;;;;; b)[(5•2•7)^2+x]-401=5•10^2;[(5•2•7)^2+x]-401=500;(5•2•7)^2+x=901;70^2+x=901;4900+x=901=>x=-3999(in acest caz multimea solutiilor ecuatiei este S=multimea vida ,deoarece x nu apartine N)