Gọi phần (.....) là x, ta có:
\(\frac{8}{15}+\frac{4}{15}+\frac{6}{15}=x\cdot\frac{2}{15}\)
\(\Rightarrow\frac{18}{15}=x\cdot\frac{2}{15}\)
\(\Rightarrow x\cdot\frac{2}{15}=\frac{18}{15}\)
\(\Rightarrow x=\frac{18}{15}:\frac{2}{25}\)
\(\Rightarrow x=9\)
Vậy x=9.
rút gon
a,\(\frac{2.5^{22}-9.5^{21}}{25^{10}}\)
b,\(\frac{5\left(3.7^{15}-19.7^{14}\right)}{7^{16}+3.7^{15}}\)
c,\(\frac{\left(\left(-2\right)^2\right)^3.\left(-4\right)^2}{\left(-2\right)^3.\left(-2\right)^2}\)
d,\(\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
e,\(2^3+3.\left(\frac{1}{8}\right)^0-\left(\frac{1}{2^2}\right).4+\left[\left(-2\right)^2:\frac{1}{2}\right].8\)
f,\(\frac{\left(\frac{2}{5}\right)^7.5^5+\left(\frac{9}{4}\right)^3:\left(\frac{3}{16}\right)^3}{2^7.5^2+512}\)
so sánh \(\frac{4^{15}}{7^{30}}\) và \(\frac{8^{10}.3^{10}}{7^{30}.4^{15}}\)
Giúp bài này hộ mk nha. Mk đg cần gấp huhu
. Chú ý dấu chấm là nhân nha. 
a) \(2016+\frac{0,2+0,375+\frac{5}{11}}{-0,3+\frac{9}{10}-\frac{15}{22}}\)
b)\(\frac{1,11+0,19-13,2}{2,06+0,54}-\left(\frac{1}{2}+\frac{1}{3}\right):2\)
c)\(-1\frac{5}{7}.15+\frac{2}{7}.\left(-15\right)+\left(-105\right).\left(\frac{2}{3}-\frac{4}{5}+\frac{1}{7}\right)\)
Tìm giá trị của các biểu thức sau:
a)\(\frac{45^{10}.5^{20}}{75^{15}}\)
b)\(\frac{\left(0,8\right)^5}{\left(0,4\right)^6}\)
c)\(\frac{2^{15}.9^4}{6^6.8^3}\)
Tính giá trị của biểu thức:
a) A= (153 + 5. 152 - 53) : ( 183 + 6. 182 - 63)
b) \(B=\left(\frac{1}{2}-1\right)\left(\frac{1}{3}-1\right)\left(\frac{1}{4}-1\right)...\left(\frac{1}{2012}-1\right)\)
c) \(C=\frac{-1}{1.2}.\frac{-2^2}{2.3}.\frac{-3^2}{3.4}...\frac{-99^2}{99.100}.\frac{-100^2}{100.101}\)
a/ \(\frac{-15}{12}x+\frac{3}{7}=\frac{6}{5}x-\frac{1}{2}\)
b/\(\frac{12+x}{7}=\frac{x-4}{3}\)
Thực hiện phép tính
a)\(16\frac{2}{7}:\left(\frac{-3}{5}\right)+28\frac{2}{7}:\frac{3}{5}\)
b)\(\left(2^2:\frac{4}{3}-\frac{1}{2}\right).\frac{6}{5}-17\)
c)\(\left(\frac{1}{3}\right)^{50}.\left(-9\right)^{25}-\frac{2}{3}:4\)
d)\(\frac{3}{5}:\left(\frac{-1}{15}-\frac{1}{6}\right)+\frac{3}{5}:\left(\frac{-1}{3}-1\frac{1}{15}\right)\)
e)\(\left(-6,5\right).5,7+5,7.\left(-3,5\right)\)
Cho P= \(\frac{1}{2}.\frac{3}{4}.\frac{5}{6}.....100.\) Chứng tỏ rằng \(\frac{1}{15}< P< \frac{1}{10}\)
Bài 7: Tính giá trị biểu thức:
a) A = \(\left(\frac{\frac{1}{4}-\frac{1}{4}+\frac{1}{9}}{\frac{1}{9}}\right):\left(\frac{\frac{2}{3}+\frac{7}{15}}{\frac{2}{5}-\frac{1}{6}}\right)\)
b) B = (0,8.7+0,64).(1,25.7-\(\frac{4}{6}\).1,25) +31,64
