Question

Calcule o valor das expressões númericas:

a) (-2)² + 2-¹ =

b) (-2)4.4-² - (-2)³ =

c) (2 + 2 -¹) / 4 -¹ 

Answer 1

a) $(-2)^{2} + 2^{-1} =4+ \frac{1}{2} = \frac{8+1}{2} = \frac{9}{2}$

b) $(-2).4. 4^{-2} - (-2)^{3} =-2.4. ( \frac{1}{4} )^{2} - (-8)=-2.4. ( \frac{1}{ 4^{2} } )+8$$=-2.( \frac{1}{ 4 } )+8=- \frac{1}{ 2 }+8= \frac{-1+16}{2} = \frac{15}{2}$

c) $\frac{(2+ 2^{-1}) }{ 4^{-1} } = \frac{2+ \frac{1}{2} }{ \frac{1}{4} } = \frac{\frac{4+1}{2} }{ \frac{1}{4} } = \frac{\frac{5}{2} }{ \frac{1}{4} } = \frac{5}{2} . \frac{4}{1} = 10$

Answer 2

Calcule o valor das expressões númericas:

a) (-2)² + 2-¹ =

   (-2)² +  2-¹ = 4 + 1/2¹

                acha mmc 

                       8 + 1
                       ------ = 9/2  =  ou 4,5
                          2

 b) (-2)4.4-² - (-2)³ =
     (-2)4.1   -(-2)³ =
    - 8       - (-8)
---------              =
     4²

 
- 8     + 8                                   - 8 + 128           120
------         =    achar mmc          -----------  =        ----   = 8
 16                                                 16                   16


c) (2 + 2 -¹) / 4 -¹


    (2 + 1)                         4 + 1                    5 
           ---                          ------                   ----
           2¹                              2                      2
______________= ____________  =     _______ =                                     
           1                              1                       1
          ---                            ----                     ---                                               
           4¹                             4                        4  

atenção divisão em cima de divisão COPIA O 1º E  inverte o segundo multiplicando

 Então
5      4           20
--  x  -- =       -----  = 10
2      1             2