Đáp án:
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Giải thích các bước giải:
$(\dfrac{-5}{7}):(\dfrac{-5}{7})^{39}+0,5^{19}.2^{20}-1^{43}-|\dfrac{-25}{49}|$
$=(\dfrac{-5}{7})^{1-39}+0,5^{19}.2^{19}.2-1-\dfrac{25}{49}$
$=(\dfrac{-5}{7})^{-38}+(2.0,5)^{19}.2-1-\dfrac{25}{49}$
$=(\dfrac{5}{7})^{-38}+1^{19}.2-1-\dfrac{25}{49}$
$=(\dfrac{7}{5})^{38}+2-1-\dfrac{25}{49}$
$=(\dfrac{7}{5})^{38}+1-\dfrac{25}{49}$
$=(\dfrac{7}{5})^{38}+\dfrac{49-25}{49}$
$=(\dfrac{7}{5})^{38}+\dfrac{24}{49}$
