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mình gõ hơi khó nhìn nhưng bài giải này là chính xác 100%
a,3^10.(-5)^21/(-50)^20.3^12
=3^10.(-5)^20.(-5)/(-5)^20.3^10.3^2
=-5/3^2=-5/9
câu b, bạn tách ra làm tương tự
a)\(\dfrac{3^{10}.\left(-5\right)^{21}}{\left(-5\right)^{20}.3^{12}}=\dfrac{\left(-5\right)}{9}\)
b)\(\dfrac{5^{11}.7^{12}+5^{11}.7^{11}}{5^{12}.7^{12}+9.5^{11}.7^{11}}=\dfrac{7.35^{11}+35^{11}}{35^{12}+9.35^{11}}=\dfrac{8.35^{11}}{44.35^{11}}=\dfrac{2}{11}\)
G=\(\dfrac{\left(-2\right)}{3}+\dfrac{\left(-5\right)}{7}+\dfrac{2}{3}+\dfrac{\left(-2\right)}{7}\)
\(\Rightarrow G=\dfrac{\left(-2\right)}{3}+\dfrac{2}{3}+\dfrac{\left(-5\right)}{7}+\dfrac{\left(-2\right)}{7}\)
\(\Rightarrow G=\dfrac{\left(-2\right)+2}{3}+\dfrac{\left(-5\right)+\left(-2\right)}{7}\)
\(\Rightarrow G=0+\dfrac{-7}{7}\)
\(\Rightarrow G=-1\)
\(H=\dfrac{\left(-5\right)}{7}\cdot\dfrac{2}{11}+\dfrac{\left(-5\right)}{7}\cdot\dfrac{9}{11}\)
\(\Rightarrow H=\dfrac{\left(-5\right)}{7}\cdot\left(\dfrac{2}{11}+\dfrac{9}{11}\right)\)\(\Rightarrow H=\dfrac{\left(-5\right)}{7}\cdot\left(\dfrac{2+9}{11}\right)\)
\(\Rightarrow H=\dfrac{\left(-5\right)}{7}\cdot1\)
\(\Rightarrow H=\dfrac{-5}{7}\)
\(\frac{5^{11}.7^{12}+5^{11}.7^{11}}{5^{12}.7^{12}+9.5^{11}.7^{11}}\)
=\(\frac{5^{11}.7^{11}\left(7+1\right)}{5^{11}.7^{11}\left(5.7+9\right)}\)
= \(\frac{8}{35+9}\)
= \(\frac{8}{44}\)
= \(\frac{2}{11}\)
Hai câu a) và b) bạn chỉ cần xem số mũ rồi trừ số mũ là xong
\(c)\) \(\frac{2^{10}.3^{10}-2^{10}.3^9}{2^9.3^{10}}=\frac{2^{10}.3^9\left(3-1\right)}{2^9.3^{10}}=\frac{2^{10}.3^9.2}{2^9.3^{10}}=\frac{2^{11}.3^9}{2^9.3^{10}}=\frac{2^2}{3}=\frac{4}{3}\)
\(d)\) \(\frac{5^{11}.7^{12}+5^{11}.7^{11}}{5^{12}.7^{12}+9.5^{11}.7^{11}}=\frac{5^{11}.7^{11}\left(7+1\right)}{5^{11}.7^{11}\left(5.7+9\right)}=\frac{8}{35+9}=\frac{8}{44}=\frac{2}{11}\)
Chúc bạn học tốt
\(\frac{5^{11}\cdot7^{12}+5^{11}\cdot7^{11}}{5^{12}\cdot7^{11}+9\cdot5^{11}\cdot7^{11}}\)
=\(\frac{5^{11}\cdot\left(7^{12}+7^{11}\right)}{5^{11}\left(5\cdot7^{11}+9\cdot7^{11}\right)}\)
=\(\frac{7^{12}+7^{11}}{5\cdot7^{11}+9\cdot7^{11}}\)
=\(\frac{7^{11}\left(7+1\right)}{7^{11}\left(5+9\right)}\)
=\(\frac{8}{14}=\frac{4}{7}\)
Kết quả này chắc chắn là đúng đấy
Giải:
a) \(A=\dfrac{5}{13}.\dfrac{5}{7}+\dfrac{-20}{41}+\dfrac{5}{13}+\dfrac{-21}{41}\)
\(\Leftrightarrow A=\dfrac{5}{13}.\dfrac{5}{7}+\dfrac{5}{13}+\dfrac{-21}{41}+\dfrac{-20}{41}\)
\(\Leftrightarrow A=\dfrac{5}{13}\left(\dfrac{5}{7}+1\right)+\dfrac{-41}{41}\)
\(\Leftrightarrow A=\dfrac{5}{13}.\dfrac{12}{7}+\left(-1\right)\)
\(\Leftrightarrow A=\dfrac{60}{91}+\left(-1\right)=-\dfrac{31}{91}\)
Vậy ...
b) \(B=\dfrac{5}{7}.\dfrac{2}{11}+\dfrac{5}{7}.\dfrac{12}{11}-\dfrac{5}{7}.\dfrac{7}{11}\)
\(\Leftrightarrow B=\dfrac{5}{7}\left(\dfrac{2}{11}+\dfrac{12}{11}-\dfrac{7}{11}\right)\)
\(\Leftrightarrow B=\dfrac{5}{7}.\dfrac{7}{11}\)
\(\Leftrightarrow B=\dfrac{5}{11}\)
Vậy ...
c) \(C=\dfrac{-2}{3}+\dfrac{-5}{7}+\dfrac{2}{3}+\dfrac{-2}{7}\)
\(\Leftrightarrow C=\left(\dfrac{-2}{3}+\dfrac{2}{3}\right)+\left(\dfrac{-2}{7}+\dfrac{-5}{7}\right)\)
\(\Leftrightarrow C=0+\left(-1\right)=-1\)
Vậy ...
a
\(\dfrac{121.75.130.169}{39.60.11.198}\\ =\dfrac{11.11.5.5.3.13.2.5.13.13}{13.3.2.2.3.5.11.18.11}\\ =\dfrac{5.13.5.13}{2.3.18}\\ =\dfrac{65.65}{108}\\ =\)
tự tính
\(b\\ \dfrac{5^{11}.7^{12}+5^{11}.7^{11}}{5^{12}.7^{12}.9.5^{11}.7^{11}}\\ =\dfrac{5^{11}.7^{11}.2.7}{5^{12}.7^{11}.7.9.5^{11}.7^{11}}\\ =\dfrac{2}{5^{12}.7^{11}.9.}\\ =\)\
tự tính nhé