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\(1\frac{4}{23}-\frac{5}{21}-\frac{4}{23}+2014-\frac{16}{21}\)
\(=\left(1\frac{4}{23}-\frac{4}{23}\right)-\left(\frac{5}{21}+\frac{16}{21}\right)+2014\)
= 1 - 1 + 2014
= 0 + 2014 = 2014
\(A=\left(x^3x^2x^3\right).\left(yy^4\right).\left(-\frac{5}{4}.\frac{2}{5}\right)=-\frac{1}{2}x^8y^5\)
\(B=\left(x^5xx^2\right).\left(y^4y^2y^5\right).\left(-\frac{3}{4}.\frac{-8}{9}\right)=\frac{2}{3}x^8y^{11}\)
Bây giờ tạm gọi các biểu thức ở mỗi bài lần lượt là A;B;C;...
a/\(A=3^2.\frac{1}{3^5}.3^8.\frac{1}{3^3}=3^2=9\)
b/\(B=\frac{3^{10}.3^5.5^5}{-5^6.3^{14}}=\frac{-3}{5}\)
c/\(C=2^3+3.1-\frac{1}{2^2}.2^2+\frac{2^2}{2}.2^3=8+3-1+16=26\)
d/\(D=\frac{3^4}{2^8}.\frac{2^{12}}{3^8}=\frac{2^4}{3^4}=\frac{16}{81}\)
e/\(E=\frac{-31^3}{2^9}.\frac{2^{20}}{31^4}=\frac{-2^{11}}{31}=\frac{-2048}{31}\)
f/\(F=\frac{-3^5}{2^{10}}.\frac{2^{20}}{3^{10}}=\frac{-2^{10}}{3^5}=\frac{-1024}{243}\)
Gửi tạm trước 2 câu !
\(a,\text{ }3^2\cdot\frac{1}{243}\cdot81^2\cdot3^{-3}=3^2\cdot\frac{1}{3^5}\cdot\left(3^4\right)^2\cdot\frac{1}{3^3}=3^2\cdot\frac{1}{3^5}\cdot3^8\cdot\frac{1}{3^3}=3^2=9\)\(b,\text{ }\frac{\left(-3\right)^{10}\cdot15^5}{25^3\cdot\left(-9\right)^7}=\frac{3^{10}\cdot\left(3\cdot5\right)^5}{\left(5^2\right)^3\cdot\left(-3\cdot3\right)^7}=\frac{3^{10}\cdot3^5\cdot5^5}{5^6\cdot3^7\cdot\left(-3\right)^7}=\frac{3^{15}\cdot5^5}{5^6\cdot3^7\cdot\left(-3\right)^7}=\frac{3}{-5}\)
Trả lời :
\(a,\text{ }3^2\cdot\frac{1}{243}\cdot81^2\cdot3^{-3}=3^2\cdot\frac{1}{3^5}\cdot\left(3^4\right)^2\cdot\frac{1}{3^3}=3^2\cdot\frac{1}{3^5}\cdot3^8\cdot\frac{1}{3^3}=3^2=9\)\(b,\text{ }\frac{\left(-3\right)^{10}\cdot15^5}{25^3\cdot\left(-9\right)^7}=\frac{3^{10}\cdot\left(3\cdot5\right)^5}{\left(5^2\right)^3\cdot\left(-3\cdot3\right)^7}=\frac{3^{10}\cdot3^5\cdot5^5}{5^6\cdot3^7\cdot\left(-3\right)^7}=\frac{3^{15}\cdot5^5}{5^6\cdot3^7\cdot\left(-3\right)^7}=\frac{3}{-5}\)
\(A = {1\over2}-{3\over4}+{5\over6}-{7\over12}={6\over12}-{9\over12}+{10\over12}-{7\over12}\)\(={0\over12}=0\)
a)\(\left(\frac{4}{5}\right)^{2x+7}=\left(\frac{4}{5}\right)^4\)
=> 2x + 7 = 4
2x = 4 - 7
2x = -3
x = -3 : 2
x = -1,5
Vậy x = -1,5


$$= \frac{3}{4} : \left(\frac{6}{9} - \frac{5}{9}\right) + \frac{9}{4}$$$$= \frac{3}{4} : \frac{1}{9} + \frac{9}{4}$$$$= \frac{3}{4} \times 9 + \frac{9}{4}$$$$= \frac{27}{4} + \frac{9}{4}$$$$= \frac{36}{4} = 9$$\(= \frac{3}{4} : \left( \frac{6}{9} - \frac{5}{9} \right) + \frac{9}{4}\)
\(= \frac{3}{4} : \frac{1}{9} + \frac{9}{4}\)
\(= \frac{3}{4} \times 9 + \frac{9}{4}\)
\(= \frac{27}{4} + \frac{9}{4}\)
\(= \frac{36}{4}\)
\(= 9\)
Ta có:
3/4 : (2/3 - 5/9) + 9/4
= 3/4 : (6/9 - 5/9) + 9/4
= 3/4 : 1/9 + 9/4
= 3/4 × 9 + 9/4
= 27/4 + 9/4
= 36/4
= 9
Đáp số: 9.