Tính:
a)\(\frac{5\cdot18-10\cdot27+15\cdot36}{10\cdot36-20\cdot54+30\cdot27}\)
b)\(\frac{\frac{-6}{7}+\frac{6}{19}-\frac{6}{31}}{\frac{9}{7}-\frac{9}{19}+\frac{9}{31}}\)
Tính \(A=\left(\frac{1}{4\cdot9}+\frac{1}{9\cdot14}+\frac{1}{14\cdot19}+...+\frac{1}{44\cdot49}\right)\cdot\frac{1-3-5-7-...-49}{89}\)
\(B=\frac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^{10}\cdot6^{19}-7\cdot2^{29}\cdot27^6}-\frac{2^{19}\cdot27^3+15\cdot4^9\cdot9^4}{6^9\cdot2^{10}+12^{10}}\)
bài này không khó. Nhưng đánh máy để giải cho bạn thì thực sự khó
Tinh
A=\(\frac{15\cdot3^{11}+4\cdot27^1}{9^7}\)
B=\(\frac{5\cdot2^{13}+4^{11}-1}{\left(3\cdot2^{17}\right)^2}\)
C=\(\frac{2^{19}\cdot27^3+15\cdot4^9\cdot9^4}{6^9\cdot2^{10}+12^{10}}\)
\(A=\frac{15.3^{11}+4.27^1}{9^7}\)
\(\Rightarrow A=\frac{3.5.3^{11}+4.3^{3^1}}{\left(3^2\right)^7}\)
\(\Rightarrow A=\frac{3^{12}.5+4.3^3}{3^{14}}\)
\(\Rightarrow A=\frac{3^3.\left(5.3^8+4.3^3\right)}{3^{14}}\)
\(\Rightarrow A=\frac{32805+4}{177147}\)
\(\Rightarrow A=\frac{32809}{177147}\)
tính nhanh :
\(B=\frac{1}{3\cdot7}+\frac{1}{7\cdot11}+\frac{1}{11\cdot15}+\frac{1}{15\cdot19}+\frac{1}{19\cdot23}+\frac{1}{23\cdot27}+\frac{1}{27\cdot31}+\frac{1}{31\cdot35}\)
\(A=\frac{1}{3}-\frac{3}{5}+\frac{5}{7}-\frac{7}{9}+\frac{9}{11}-\frac{11}{13}+\frac{13}{15}+\frac{11}{13}-\frac{9}{11}+\frac{7}{9}-\frac{5}{7}+\frac{3}{5}-\frac{1}{3}\)
Phần 1)Đầu tiên bạn nhân B với 1 phần 4 rồi tính đến đoạn gần cuối sẽ ra 1/3 - 1/35 rồi quy đòng rồi tính sẽ ra kêt quả cuối là 32/105 nha
Mình lười lắm nên chỉ help 1 phần thui nha sr
tính
\(\frac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^{10}\cdot6^{19}-7\cdot2^{29}\cdot27^6}\)
\(\frac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^{10}.6^{19}-7.2^{29}.27^6}\)
\(=\frac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{5.2^{10}.2^{19}.3^{19}-7.2^{29}.3^{18}}\)
\(=\frac{5.2^{30}.3^{18}-2^{29}.3^{20}}{5.2^{29}.3^{19}-7.2^{29}.3^{18}}\)
\(=\frac{2^{29}.3^{18}\left(5.2-3^2\right)}{2^{29}.3^{18}\left(5.3-7\right)}\)
\(=\frac{10-9}{15-7}\)
\(=\frac{1}{8}\)
\(\frac{12^2\cdot4^{16}}{11\cdot2^{13}\cdot4^{11}-16^9}+\frac{7\cdot9+14\cdot27+21\cdot36}{21\cdot27+42\cdot81+63\cdot108}\)
tính giá trị biểu thức
\(B=\frac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^9\cdot6^{19}-7\cdot2^{29}\cdot27^6}\)
\(C=\frac{2181\cdot729+243\cdot81\cdot27}{3^2\cdot9^2\cdot243+18\cdot54\cdot162\cdot9+723\cdot729}\)
lời giải nữa nhé
\(A=2000\)
\(B=\frac{-2}{11}\)
\(C=1\)
\(D=\frac{11}{10}\)
Nát óc mới làm được
k ủng hộ nhá
\(B=\frac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^9\cdot6^{19}-7\cdot2^{29}\cdot27^6}\)
\(\frac{5\cdot4^{15}-9^9-4\cdot3^{20}\cdot89}{5\cdot29\cdot6^{19}-7\cdot2^{29}\cdot27^6}\)
Tính nhanh:
\(\frac{\frac{-6}{7}+\frac{6}{19}-\frac{6}{31}}{\frac{9}{7}-\frac{9}{19}+\frac{9}{31}}\)
\(\frac{\frac{-6}{7}+\frac{6}{19}+\frac{-6}{31}}{\frac{9}{7}+\frac{-9}{19}+\frac{9}{31}}=\frac{-2\times\left(\frac{3}{7}+\frac{-3}{19}+\frac{3}{31}\right)}{3\times\left(\frac{3}{7}+\frac{-3}{19}+\frac{3}{31}\right)}\)
\(=\frac{-2}{3}\)