Question

Решите уравнение
a) $27^{3x} =frac{1}{3}$
б)$5^{2x+1} -5^{x}=4$

Answer 1

$a) {3}^{9x} = {3}^{ - 1} \ 9x = - 1 \ x = - frac{1}{9}$
${5}^{2x} times 5 - {5}^{x} - 4 = 0 \ {5}^{x} = a \ 5 {a}^{2} - a - 4 = 0 \ d = 1 - 4 times 5 times ( - 4) = 81 \ a1 = frac{ - ( - 1) - sqrt{81} }{2 times 5} = frac{1 - 9}{10} = - 0.8 \ a2 = frac{ - ( - 1) + 9}{2 times 5} = frac{10}{10} = 1 \ {5}^{x} = - 0.8 : ne : mozhet : byt \ {5}^{x} = 1 \ x = 0$