Toán (-5/7):(-5/7)^39+0,5^19.2^20-1^43-|-25/49| 11/08/2021 By Liliana (-5/7):(-5/7)^39+0,5^19.2^20-1^43-|-25/49|
Giải thích các bước giải: $(\dfrac{-5}{7}):(\dfrac{-5}{7})^{39}+0,5^{19}.2^{20}-1^{43}-|\dfrac{-25}{49}|$ $=(\dfrac{-5}{7})^{1-39}+0,5^{19}.2^{19}.2-1-\dfrac{25}{49}$ $=(\dfrac{-5}{7})^{-38}+(2.0,5)^{19}.2-1-\dfrac{25}{49}$ $=(\dfrac{5}{7})^{-38}+1^{19}.2-1-\dfrac{25}{49}$ $=(\dfrac{7}{5})^{38}+2-1-\dfrac{25}{49}$ $=(\dfrac{7}{5})^{38}+1-\dfrac{25}{49}$ $=(\dfrac{7}{5})^{38}+\dfrac{49-25}{49}$ $=(\dfrac{7}{5})^{38}+\dfrac{24}{49}$ Trả lời
Giải thích các bước giải:
$(\dfrac{-5}{7}):(\dfrac{-5}{7})^{39}+0,5^{19}.2^{20}-1^{43}-|\dfrac{-25}{49}|$
$=(\dfrac{-5}{7})^{1-39}+0,5^{19}.2^{19}.2-1-\dfrac{25}{49}$
$=(\dfrac{-5}{7})^{-38}+(2.0,5)^{19}.2-1-\dfrac{25}{49}$
$=(\dfrac{5}{7})^{-38}+1^{19}.2-1-\dfrac{25}{49}$
$=(\dfrac{7}{5})^{38}+2-1-\dfrac{25}{49}$
$=(\dfrac{7}{5})^{38}+1-\dfrac{25}{49}$
$=(\dfrac{7}{5})^{38}+\dfrac{49-25}{49}$
$=(\dfrac{7}{5})^{38}+\dfrac{24}{49}$