Tính
a, 4\(\times\left(-\dfrac{1}{2}\right)^3-2\times\left(-\dfrac{1}{2}\right)^2+3\times\left(-\dfrac{1}{2}\right)+1\)
b, \(\dfrac{4^6\times9^5+6^9\times120}{-8^4\times3^{12}+6^{11}}\)
c, \(\dfrac{155-\dfrac{10}{7}-\dfrac{5}{11}+\dfrac{5}{23}}{403-\dfrac{26}{7}-\dfrac{13}{11}+\dfrac{12}{23}}+\dfrac{\dfrac{3}{5}+\dfrac{3}{13}-0,9}{\dfrac{7}{91}+0,2-\dfrac{3}{10}}\)
d,\(\dfrac{30\times4^7\times3^{29}-5\times14^5\times2^{12}}{54\times6^{14}\times9^7-12\times8^5\times7^5}\)
a, \(4\times\left(-\dfrac{1}{2}\right)^3-2\times\left(-\dfrac{1}{2}\right)^2+3\times\left(-\dfrac{1}{2}\right)+1\)
\(=\left(-\dfrac{1}{2}\right)\left[\left(4\times-\dfrac{1}{2}\right)-\left(2\times-\dfrac{1}{2}\right)+3\right]+1\)
\(=\left(-\dfrac{1}{2}\right)\left(-2+1+3\right)+1\)
\(=\left(-\dfrac{1}{2}\right)2+1\)
\(=-1+1\)
\(=0\)
@Trịnh Thị Thảo Nhi
a, 4×(−12)3−2×(−12)2+3×(−12)+14×(−12)3−2×(−12)2+3×(−12)+1
=(−12)[(4×−12)−(2×−12)+3]+1=(−12)[(4×−12)−(2×−12)+3]+1
=(−12)(−2+1+3)+1=(−12)(−2+1+3)+1
=(−12)2+1=(−12)2+1
=−1+1=−1+1
=0=0
\(C=\dfrac{5\times4^6\times9^4-3^9\times\left(-8\right)^4}{4\times2^{13}\times3^8+2\times8^4\times\left(-27\right)^3}\)
\(C=\dfrac{5\times2^{12}\times3^8-3^9\times2^{12}}{2^2\times2^{13}\times3^8+2\times2^{12}\times\left(-3^9\right)}=\dfrac{3^8\times2^{12}\times\left(5-3\right)}{2^{15}\times3^8+2^{13}\times\left(-3\right)^9}\)
\(=\dfrac{3^8\times2^{12}\times2}{2^{13}\times3^8\times\left(4-3\right)}=\dfrac{1}{1}=1\)
\(#PaooNqoccc\)
\(\dfrac{4^{10}\times9^6+3^{12}\times8^5}{6^{13}\times4+2^{16}\times3^{12}}\)
Lời giải:
Gọi biểu thức trên là $A$
\(A=\frac{2^{20}.3^{12}+3^{12}.2^{15}}{2^{13}.3^{13}.2^2+2^{16}.3^{12}}=\frac{2^{20}.3^{12}+3^{12}.2^{15}}{2^{15}.3^{13}+2^{16}.3^{12}}\)
\(=\frac{2^{15}.3^{12}(2^5+1)}{2^{15}.3^{12}(3+2)}=\frac{2^5+1}{5}=\frac{33}{5}\)
Tính nhanh:\(\frac{1\times2\times3+2\times4\times6+3\times6\times9+4\times8\times12+5\times10\times15}{1\times3\times5+2\times6\times10+3\times9\times15+4\times12\times20+5\times15\times25}-\frac{1+2+3+2+4+6+3+6+9+4+8+12+5+10+15}{1+3+5+2+6+10+3+9+15+4+12+20+5+15+25}\)
Thực hiện phép tính
a, A = \(\left(\dfrac{1}{4\times9}+\dfrac{1}{9\times14}+\dfrac{1}{14\times19}+....+\dfrac{1}{44\times49}\right)\times\dfrac{1-3-5-7-....-49}{89}\)
b, B = \(\dfrac{2^{12}\times3^5-4^6\times9^2}{\left(2^2\times3\right)^6+8^4\times3^5}-\dfrac{5^{10}\times7^3-25^5\times49^2}{\left(125\times7\right)^3-5^9\times14^3}\)
Tính giá trị biểu thức:
a. \(\dfrac{20^5\times5^{10}}{100^5}\)
b. \(\dfrac{\left(0,9\right)^5}{\left(0,3\right)^6}\)
c. \(\dfrac{6^3+3\times6^2+3^3}{-13}\)
d. \(\dfrac{4^6\times9^5+6^9\times120}{8^4\times3^{12}-6^{11}}\)
e. \(\left(2^{-1}+3^{-1}\right):\left(2^{-1}-3^{-1}\right)+\left(2^{-1}\times2^0\right)\times2^3\)
f. \(\left(\dfrac{-1}{3}\right)^{-1}-\left(\dfrac{-3}{5}\right)^6+\left(\dfrac{1}{2}\right)^2:2\)
a, \(\dfrac{20^5.5^{10}}{100^5}=\dfrac{20^5.5^{10}}{\left(20.5\right)^5}=\dfrac{20^5.5^{10}}{20^5.5^5}=5^5\)
b,\(\dfrac{\left(0,9\right)^5}{\left(0,3\right)^6}=\dfrac{\left(0,3.3\right)^5}{\left(0,3\right)^6}=\dfrac{\left(0,3\right)^5.3^5}{\left(0,3\right)^6}=\dfrac{3^5}{\left(0,3\right)}\)
c, \(\dfrac{6^3+3.6^2+3^3}{-13}=\dfrac{6^2.\left(6+3\right)+3^3}{-13}=\dfrac{6^2.9+3^3}{-13}\)=\(\dfrac{3^2.\left(36+3\right)}{-13}=\dfrac{3^2.39}{-13}=-27\)
Tính giá trị của mỗi phân số sau:
\(E=\dfrac{11\times3^{29}-\left(3^2\right)^{15}}{2\times3^{14}\times2\times3^{14}}\)
\(G=\dfrac{5\times3^{11}+4\times3^{12}}{3^9\times5^2-3^0\times2^3}\)
\(H=\dfrac{\left(3\times4\times2^{16}\right)^2}{11\times2^{13}\times4^{11}-16^9}\)
\(E=\dfrac{11.3^{29}-3^{2^{15}}}{2.3^{14}.2.3^{14}}\)
\(=\dfrac{11.3-3^{30}}{2^2}=\dfrac{33-3^{30}}{4}\)
\(E=\dfrac{5\times4^{15}\times9^9-4\times3^{20}\times8^9}{5\times2^{10}\times6^{19}-7\times2^{29}\times27^6}\)
\(\dfrac{5\times4^{15}\times9^9-4\times3^{20}\times8^9}{5\times2^{10}\times6^{19}-7\times2^{29}\times27^6}\\ =\dfrac{5\times2^{30}\times3^{18}-2^2\times3^{20}\times2^{27}}{5\times2^{10}\times3^{19}\times2^{19}-7\times2^{29}\times3^{18}}\\ =\dfrac{5\times2^{30}\times3^{18}-2^{29}\times3^{20}}{5\times2^{29}\times3^{19}-7\times2^{29}\times3^{18}}\\ =\dfrac{2^{29}\times3^{18}\times\left(5\times2-3^2\right)}{2^{29}\times3^{18}\times\left(5\times3-7\right)}\\ =\dfrac{10-9}{15-7}\\ =\dfrac{1}{8}\)
Goridano
Tổng của hai số đầu là
\(\dfrac{5}{12}\times2=\dfrac{10}{12}\left(1\right)\)
Tổng của 3 số đầu là:
\(\dfrac{19}{36}\times3=\dfrac{19}{12}\left(2\right)\)
Tổng của 4 số là:
\(\dfrac{143}{249}\times4=\dfrac{143}{60}\)
Từ (1) và (2), ta thấy số thứ 3 là: \(\dfrac{19}{12}-\dfrac{10}{12}=\dfrac{48}{60}=\dfrac{4}{5}\)
Từ (2) và (3), ta thấy số cuối là:
\(\left(\dfrac{3}{4}+\dfrac{4}{5}\right)\div2=\dfrac{31}{40}\)
Số đầu là:
\(\dfrac{31}{40}-\dfrac{1}{10}=\dfrac{20}{40}=\dfrac{1}{2}\)
Theo (1), số thứ 2 là:
\(\dfrac{10}{12}-\dfrac{1}{2}=\dfrac{4}{12}=\dfrac{1}{3}\)
Đáp số : \(\dfrac{1}{2};\dfrac{1}{3};\dfrac{3}{4};\dfrac{4}{5}\)
