Question

Ajuda com essas duas questões de equação exponencial ???
Por favor

Answer 1

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16)

$(2^x)^{x-1}=4 \\ \\ 2^{ x^{2} -x}=2^2 \\ \\ x^{2} -x-2=0 \\ \\ \triangle=1^2+8=9 \\ \\ x= \frac{1\pm \sqrt{9} }{2} = \frac{1\pm3}{2} \\ \\ x'= \frac{1+3}{2} = \frac{4}{2} =2 \\ \\ x"= \frac{1-3}{2} =- \frac{2}{2} =-1 \\ \\ x'.x"=2(-1)=-2~~~letra~~B$

17)

$0,25^{x-4}=0,5^{-2x+1} \\ \\ (0,5^2)^{x-4}=0,5^{-2x+1} \\ \\ 2(x-4)=-2x+1 \\ \\ 2x-8=-2x+1 \\ \\ 2x+2x=+1+8 \\ \\ 4x=9 \\ \\ x= \frac{9}{4} ~~~~letra~~D$