Question

RESOLVA AS INEQUAÇOES
A) 3 ^ x - 5 > 81

B) 7 . 2 ^ 3x < 56

AJUDA PF

Answer 1

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$a)~~~3^{x-5}\ \textgreater \ 81 \\ \\ \not3^{x-5}\ \textgreater \ \not3^4 \\ \\ x-5\ \textgreater \ 4 \\ \\ x\ \textgreater \ 4+5 \\ \\ x\ \textgreater \ 9 \\ \\ S=\{x\in~R/ x\ \textgreater \ 9\} \\ \\ \\ b)~~7.2^{3x}\ \textless \ 56 \\ \\ 2^{3x}\ \textless \ 56\div7 \\ \\ 2^{3x}\ \textless \ 8 \\ \\\not 2^{3x}\ \textless \ \not2^ 3 \\ \\ 3x\ \textless \ 3 \\ \\ x\ \textless \ 3\div3 \\ \\ x\ \textless \ 1 \\ \\ S=\{x\in R/x\ \textless \ 1\}$