Tính hợp lí :M=1-5/√196-5/(2√21)^2-√25/204-(√5)^2/374
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(M=1-\dfrac{5}{14}-\dfrac{5}{84}-\dfrac{5}{204}-\dfrac{5}{374}\)
\(=\dfrac{84-30-5}{84}-\dfrac{5}{204}-\dfrac{5}{374}\)
\(=\dfrac{49}{84}-\dfrac{5}{204}-\dfrac{5}{374}\)
\(=\dfrac{7}{12}-\dfrac{5}{204}-\dfrac{5}{374}\)
\(=\dfrac{7\cdot17-5}{204}-\dfrac{5}{374}=\dfrac{19}{34}-\dfrac{5}{374}=\dfrac{204}{374}=\dfrac{6}{11}\)
Lần sau nhớ đăng đúng chỗ nhá
M=\(1-\dfrac{5}{\sqrt{196}}-\dfrac{5}{\left(2\sqrt{21}\right)^2}-\dfrac{\sqrt{25}}{204}-\dfrac{\left(\sqrt{5}\right)^2}{374}\)
\(M=1-\dfrac{5}{14}-\dfrac{5}{84}-\dfrac{5}{204}-\dfrac{5}{374}\)
M=\(\dfrac{15708-5610-935-385-210}{15708}\)
\(\Rightarrow M=\dfrac{6}{11}\)
\(M=1-\frac{5}{\sqrt{196}}-\frac{5}{\left(2\sqrt{21}\right)^2}-\frac{\sqrt{25}}{204}-\frac{\left(\sqrt{5}\right)^2}{374}\)
\(=1-\frac{5}{14}-\frac{5}{84}-\frac{5}{204}-\frac{5}{374}\left(\text{(}2\sqrt{21}\text{)}^2=2^2.21=84\right)\)
\(=1-\frac{5}{2.7}-\frac{5}{7.12}-\frac{5}{12.17}-\frac{5}{17.22}\)
\(=1-\frac{1}{2}+\frac{1}{7}-\frac{1}{7}+\frac{1}{12}-\frac{1}{12}+\frac{1}{17}-\frac{1}{17}+\frac{1}{22}\)
\(=1-\frac{1}{2}+\frac{1}{22}\)
\(=\frac{22-11+1}{22}=\frac{12}{22}=\frac{6}{11}\)
Vậy M = 6/11.
Giải:
\(A=1-\dfrac{5}{\sqrt{196}}-\dfrac{5}{\left(2.\sqrt{21}\right)^2}-\dfrac{\sqrt{25}}{204}-\dfrac{\left(\sqrt{5}\right)^2}{374}\)
\(\Leftrightarrow A=1-\dfrac{5}{14}-\dfrac{5}{2^2.\left(\sqrt{21}\right)^2}-\dfrac{5}{204}-\dfrac{5}{374}\)
\(\Leftrightarrow A=1-\dfrac{5}{14}-\dfrac{5}{84}-\dfrac{5}{204}-\dfrac{5}{374}\)
\(\Leftrightarrow A=\dfrac{5}{5}-\dfrac{5}{14}-\dfrac{5}{84}-\dfrac{5}{204}-\dfrac{5}{374}\)
\(\Leftrightarrow A=5\left(\dfrac{1}{5}-\dfrac{1}{14}-\dfrac{1}{84}-\dfrac{1}{204}-\dfrac{1}{374}\right)\)
\(\Leftrightarrow A=5.\dfrac{6}{55}\)
\(\Leftrightarrow A=\dfrac{6}{11}\)
Vậy giá trị của biểu thức A là \(\dfrac{6}{11}\).
Chúc bạn học tốt!