Question

Por Favor Encontre o valor de 16x-² - 8x-¹+4-¹,para x=(1/2)elevado a -4
a)-7/16 b)-3/16 c)-5/16 d)7/16 e)1/16

Answer 1

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$16[( \frac{1}{2} )^{-4}]^{-2}-8[( \frac{1}{2} )^{-4}]^{-1}+4^{-1}= \\ \\ 16( \frac{1}{2} )^8-8( \frac{1}{2} )^4+ \frac{1}{4} = \\ \\ 16( \frac{1}{256} )-8( \frac{1}{16} )+ \frac{1}{4} = \\ \\ simplificando \\ \\ \frac{1}{16} - \frac{1}{2} + \frac{1}{4} = \\ \\ mmc(2,4,16)=16 \\ \\ \frac{1-8+4}{16} = \\ \\ \fbox{ - \frac{3}{16} }$

Letra B