Question

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Answer 1

2^x - 14* 1/(2^x) = -5 Notam 2^x = t , t>0 t - 14/t +5 = 0 t² + 5t - 14 = 0 Delta = 25-4*1*(-14) = 25+56 = 81  t1 = (-5+9)/2 = 4/2 = 2 convine t2 = (-5-9)/2 = -14/2 = -7<0, nu convine Revenim la substitiutie 2^x = 2 => x = 1 (o singura solutie) => b) 1