Có: \(\dfrac{5^2.6^9.10+6^5.2^3.15^3}{5^2.6^8.10-2.6^8.10}=\dfrac{5^2.2^9.3^9.2.5+2^5.3^5.2^3.3^3.5^3}{5^2.2^8.3^8.2.5-2.2^8.3^8.2^3.5^3}\)
=\(\dfrac{2^{10}.3^95^3+2^8.3^8.5^3}{2^9.3^8.5^3-2^{12}.3^8.5^3}=\dfrac{2^8.3^8.5^3.\left(12+1\right)}{2^8.3^8.5^3\left(2-16\right)}\)
= \(\dfrac{12+1}{2-16}=\dfrac{-13}{14}\)
Rút gọn biểu thức:
A = \(\dfrac{4^5.9^4 - 2.6^9}{2^{10}3^8 + 6^8.20}\)
\(\dfrac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)
Rút gọn biểu thức:
A=45.94-2.69/210.38+68.20
Rút gọn :
A = \(\frac{2.8^4.27^8+4.6^9}{2^7.6^7+2^7.40.9^4}\)
B = \(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)
1. Tính:
a. \(\dfrac{-1}{4}+\dfrac{5}{6}\) b. \(\dfrac{5}{12}+\dfrac{-7}{8}\) c. \(\dfrac{-7}{6}+\dfrac{-3}{10}\) d. \(\dfrac{-3}{7}+\dfrac{5}{6}\)
2. Tính :
a. \(\dfrac{2}{14}-\dfrac{5}{2}\) b. \(\dfrac{-13}{12}-\dfrac{5}{18}\) c. \(\dfrac{-2}{5}-\dfrac{-3}{11}\) d. \(0,6--1\dfrac{2}{3}\)
3. Tính :
a. \(\dfrac{-1}{39}+\dfrac{-1}{52}\) b. \(\dfrac{-6}{9}-\dfrac{12}{16}\) c. \(\dfrac{-3}{7}-\dfrac{-2}{11}\) d.\(\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+...+\dfrac{1}{8.9}+\dfrac{1}{9.10}\)
1/Rút gọn biểu thức
a/ B=\(\dfrac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
b/C= \(\dfrac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^9.6^{19}-7.2^{29}.27^6}\)
c/D=\(\dfrac{49^{24}.125^{10}.2^8-5^{30}.7^{49}.4^5}{5^{29}.16^2.7^{48}}\)
2/tìm x biết
a/9x+1-5.32x= 324
b/\(\dfrac{1}{3}\).3x=7.32.92-2.3x
c/\(\dfrac{1}{5}\).2x+\(\dfrac{1}{3}\).2x+1=\(\dfrac{1}{5}\).27+\(\dfrac{1}{3}\).28
d/ 3x+1+2x.3x- 18x - 27=0
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Thuc hien phep tinh:
a/ \(\dfrac{5}{15}\)+ \(\dfrac{14}{15}\) -\(\dfrac{12}{9}\)+ \(\dfrac{2}{7}\)+\(\dfrac{11}{25}\) d/ (\(9\dfrac{3}{4}\):5.2+3.4.\(2\dfrac{7}{34}\)) :(\(-1\dfrac{9}{16}\))
e/ \(\dfrac{2^8.9^2}{6^4.8^2}\)
b/ 4.(\(-\dfrac{1}{2}\))^3+\(\dfrac{1}{2}\)
c/ \(\dfrac{10^3+5.10^2+5^3}{6^3+3.6^2+3^3}\)
Rút gọn
B = \(\frac{3^6.45^4-15^{13}.5^{-9}}{27^4.25^3+45^6}\)
rút gọn biểu thức khi \(\dfrac{-3}{5}\)<x<\(\dfrac{1}{7}\)
a,A=|x-\(\dfrac{1}{7}\)|-|x+\(\dfrac{3}{5}\)|+\(\dfrac{4}{5}\)
b, B=|-x+\(\dfrac{1}{7}\)|+|-x-\(\dfrac{3}{5}\)|-\(\dfrac{2}{6}\)