3(pangkat 4-x) + 3(pangkat x) - 30 = 0

[tex] {3}^{4 - x} + {3}^{x} - 30 = 0 \\ {3}^{4 - x} + {3}^{x } = 30 \\ misal \: {3}^{x} = a \\ {3}^{4} \times {3}^{ - x} + {3 }^{x} = 30 \\ \frac{ {3}^{4} }{a} + a = 30 \\ {a}^{2} + - 30a + 81 = 0 \\ (a - 27)(a - 3) = 0 \\ a = 27 \\ a = 3[/tex]
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