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\(B=\left(\frac{3}{7}\right)^5.\frac{5^8.7^5}{3^4.5^4.2^4.5^2}\)
\(B=\frac{3^5.5^8.7^5}{3^4.5^6.2^4.7^5}\)
\(B=\frac{3.5^2}{2^4}\)
\(B=\frac{75}{16}\)
Bài làm
\(a,\left(\frac{3}{7}+\frac{1}{2}\right)^2\)
\(=\left(\frac{3}{7}\right)^2+\left(\frac{1}{2}\right)^2\)
\(=\frac{9}{49}+\frac{1}{4}\)
\(=\frac{36}{196}+\frac{49}{196}\)
\(=\frac{85}{196}\)
\(b,\left(\frac{3}{4}-\frac{5}{6}\right)^2\)
\(=\left(-\frac{1}{12}\right)^2\)
\(=\frac{1}{144}\)
\(c,\frac{5^4.20^4}{25^5.4^5}\)
\(=\frac{5^4.\left(5.4\right)^4}{\left(5.5\right)^5.4^5}\)
\(=\frac{5^4.5^4.4^4}{5^5.5^5.4^5}\)
\(=\frac{1}{5.5.4}\)
\(=\frac{1}{100}\)
~ Check đúng cho minh nha. ~
# Học tốt #
\(a,\left(\frac{3}{7}+\frac{1}{2}\right)^2\)
\(< =>\left(\frac{6}{14}+\frac{7}{14}\right)^2\)
\(< =>\left(\frac{13}{14}\right)^2\)
\(< =>\frac{169}{196}\)
\(b,\left(\frac{3}{4}-\frac{5}{6}\right)^2\)
\(< =>\left(\frac{9}{12}-\frac{10}{12}\right)^2\)
\(< =>\left(\frac{-1}{12}\right)^2\)
\(< =>\frac{-1}{144}\)
\(c,\frac{5^4\cdot20^4}{25^5\cdot4^5}\)
\(< =>\frac{25^2\cdot\left(4\right)^4\cdot\left(5\right)^4}{25^5\cdot4^5}\)
\(< =>\frac{1\cdot1\cdot\left(5\right)^4}{25^3\cdot4}\)
\(< =>\frac{1\cdot25^2}{25^3\cdot4}\)
\(< =>\frac{1}{25\cdot4}\)
\(< =>\frac{1}{100}\)
f) \(\frac{3^3.\left(0,5\right)^5}{\left(1,5\right)^4}=\frac{3^3.\left(0,5\right)^5}{\left[3.\left(0,5\right)\right]^4}=\frac{3^3.\left(0,5\right)^5}{3^4.\left(0,5\right)^4}=\frac{0,5}{3}=\frac{1}{6}\)
b) \(\frac{2^3+3.2^6-4^3}{2^3+3^2}=\frac{2^3.\left(1+3.2^3-2^3\right)}{2^3+3^2}=\frac{2^3.17}{17}=2^3=8\)
Các phần còn lại tương tự, bạn tự làm nhé !
(*) Lưu ý ở những bài rút gọn có chứa lũy thừa thì bạn đưa số đó về số nguyên tố rồi thực hiện như bình thường .
VD : \(4^3=\left(2^2\right)^3=2^6\) ( đưa về số nguyên tố là 2 )
\(6^3=\left(2.3\right)^3=2^3.3^3\) ( đưa về tích hai số nguyên tố )
a) \(\left(\frac{3}{7}+\frac{1}{2}\right)^2=\left(\frac{6}{14}+\frac{7}{14}\right)^2=\left(\frac{13}{14}\right)^2=\frac{169}{196}\)
b) \(\left(\frac{3}{4}-\frac{5}{6}\right)^2=\left(\frac{9}{12}-\frac{10}{12}\right)^2=\left(-\frac{1}{2}\right)^2=\frac{1}{4}\)
d) \(\left(-\frac{10}{3}\right)^5.\left(-\frac{6}{5}\right)^4=-\frac{2560}{3}\)
e) \(\left(1+\frac{2}{3}-\frac{1}{4}\right).\left(\frac{4}{5}-\frac{3}{4}\right)^2=\frac{17}{12}.\left(\frac{1}{20}\right)^2=\frac{17}{12}.\frac{1}{400}=\frac{17}{4800}\)
f) \(2:\left(\frac{1}{2}-\frac{2}{3}\right)^3=2:\left(-\frac{1}{6}\right)^3=2:-\frac{1}{216}=-432\)
Cũng khuya rồi , mình làm câu 1 thôi nhé !
\(\frac{2.5^{22}-9.5^{21}}{25^{10}}=\frac{2.5^{22}-9.5^{21}}{\left(5^2\right)^{10}}\)
\(\frac{5^{21}.\left(2.5-9\right)}{5^{20}}=5.\left(10-9\right)=5\)
a) Ta có :
\(\left(\frac{3}{7}+\frac{1}{2}\right)^2\)
= \(\left(\frac{6}{14}+\frac{7}{14}\right)^2\)
= \(\left(\frac{13}{14}\right)^2\)
= \(\frac{169}{196}\)
b)
\(\left(\frac{3}{4}-\frac{5}{6}\right)^2\)
= \(\left(\frac{18}{24}-\frac{20}{24}\right)^2\)
= \(\left(\frac{-1}{12}\right)^2\)
= \(\frac{1}{144}\)
ý B hình như mk giải rồi thì phải
\(A=\frac{a^2.a^7.b^2.c^8}{a^5.b^3.\left(-c\right)^4}=\frac{a^9.b^2.c^8}{a^5.b^3.c^4}=\frac{a^4.c^4}{b}\)
\(B=\left(\frac{3}{7}\right)^5.\frac{\left(25\right)^4.7^5}{15^4.20^2}=\frac{3^5.\left(5^2\right)^4.7^5}{7^5.\left(3.5\right)^4.\left(4.5\right)^2}=\frac{3^5.5^8.7^5}{7^5.3^4.5^4.4^2.5^2}\)
\(=\frac{3^5.5^8.7^5}{7^5.3^4.5^6.4^2}=\frac{3.5^2}{4^2}=\frac{75}{16}\)