Question

questão 7)
dê o valor da expressão em notação científica

Answer 1

a) $(6,3\cdot 10^{-8}):(0,7\cdot 10^{-14})$

$=(63\cdot 10^{-1}\cdot 10^{-8}):(7\cdot 10^{-1}\cdot 10^{-14})\\\\ =(63\cdot 10^{-1-8}):(7\cdot 10^{-1-14})\\\\ =(63\cdot 10^{-9}):(7\cdot 10^{-15})\\\\ =\dfrac{63}{7}\cdot \dfrac{10^{-9}}{10^{-15}}\\\\\\ =9,0\cdot 10^{-9-(-15)}\\\\ =9,0\cdot 10^{-9+15}\\\\ =9,0\cdot 10^{6}$

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b) $(0,4\cdot 10^7)\cdot (1,2\cdot 10^{-8})$

$=(4\cdot 10^{-1}\cdot 10^7)\cdot (12\cdot 10^{-1}\cdot 10^{-8})\\\\ =(4\cdot 10^{-1+7})\cdot (12\cdot 10^{-1-8})\\\\ =(4\cdot 10^6)\cdot (12\cdot 10^{-9})\\\\ =4\cdot 12\cdot 10^{6}\cdot 10^{-9}\\\\ =48\cdot 10^{6-9}\\\\ =48\cdot 10^{-3}\\\\ =4,8\cdot 10^1\cdot 10^{-3}\\\\ =4,8\cdot 0^{1-3}\\\\ =4,8\cdot 10^{-2}$

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c) $(6\cdot 10^3)^2$

$=6^2\cdot (10^3)^2\\\\ =36\cdot 10^{3\,\cdot\,2}\\\\ =36\cdot 10^6\\\\ =3,6\cdot 10^1\cdot 10^6\\\\ =3,6\cdot 10^{1+6}\\\\ =3,6\cdot 10^7$

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d) $2,5\cdot 10^2-1,2\cdot 10^2$

$=(2,5-1,2)\cdot 10^2\\\\ =1,3\cdot 10^2$


Bons estudos! :-)