Respuesta :

Answer:

19)  ( [tex]\frac{-2}{5}[/tex])^2 = [tex]\frac{4}{25}[/tex]

20) -[tex]9^{2}[/tex] = -81

21)  [tex]2^{4}[/tex] = 16

Step-by-step explanation:

The only wrong ones are

19)  ( [tex]\frac{-2}{5}[/tex])^2 = [tex]\frac{4}{25}[/tex]

20) -[tex]9^{2}[/tex] = -81 ... negative is not inside a parenthesis that's why it is still negative

21) you can add another way is [tex]2^{4}[/tex] = 16

Everything else looks good.  Great job!