A = 10² - ( 5² . 4 - 4³ . 3 ) + 2³

A = 100 - ( 25 . 4 - 64 . 3 ) + 8

A = 100 - ( 100 - 192 ) + 8

A = 100 - ( - 92 ) + 8

A = 192 + 8

A = 200

10^2 - ( 5^2 . 4 - 4^3 . 3 ) + 2^3

= 100 - ( 25 . 4 - 64 . 3 ) + 8

= 100 - ( 100 - 192 ) + 8

= 100 - ( -92 ) + 8

= 192 + 8

= 200

= 251 

kết quả bằng 200 nha

A​=10^2-(5^2.4-4^3.3)+2^3=200 Tích cho mình nha

\(x:\dfrac{1}{2}=\dfrac{3}{4}+\dfrac{5}{3}\\ \Rightarrow x:\dfrac{1}{2}=\dfrac{9}{12}+\dfrac{20}{12}\\ \Rightarrow x:\dfrac{1}{2}=\dfrac{29}{12}\\ \Rightarrow x=\dfrac{29}{12}\times\dfrac{1}{2}\\ \Rightarrow x=\dfrac{29}{24}\)

\(x\div\dfrac{1}{2}=\dfrac{3}{4}+\dfrac{5}{3}\)

\(x\div\dfrac{1}{2}=\dfrac{29}{12}\)

\(x=\dfrac{29}{12}\times\dfrac{1}{2}\)

\(x=\dfrac{29}{24}\)

x : 1/2 = 29/12

x = 29/12 x 1/2

x = 29/24

\(N=\dfrac{4}{2.4}+\dfrac{4}{4.6}+\dfrac{4}{6.8}+...+\dfrac{4}{2014.2016}\)

\(=2\left(\dfrac{2}{2.4}+\dfrac{2}{4.6}+\dfrac{2}{6.8}+...+\dfrac{2}{2014.2016}\right)\)

\(=2\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{8}+...+\dfrac{1}{2014}-\dfrac{1}{2016}\right)\)

\(=2\left(\dfrac{1}{2}-\dfrac{1}{2016}\right)\)

\(=2\left(\dfrac{1008}{2016}-\dfrac{1}{2016}\right)\)

\(=2.\dfrac{1007}{2016}=\dfrac{1007}{1008}\)

Công thức đây bạn:

\(\dfrac{a}{n\left(n+a\right)}=\dfrac{1}{n}-\dfrac{1}{n+a}\)

Giải:

\(N=\dfrac{4}{2.4}+\dfrac{4}{4.6}+\dfrac{4}{6.8}+...+\dfrac{4}{2014.2016}\) 

\(N=2.\left(\dfrac{2}{2.4}+\dfrac{2}{4.6}+\dfrac{2}{6.8}+...+\dfrac{2}{2014.2016}\right)\) 

\(N=2.\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{8}+...+\dfrac{1}{2014}-\dfrac{1}{2016}\right)\) 

\(N=2.\left(\dfrac{1}{2}-\dfrac{1}{2016}\right)\) 

\(N=2.\dfrac{1007}{2016}\) 

\(N=\dfrac{1007}{1008}\) 

Công thức tính: \(\dfrac{1}{n.\left(n+1\right)}=\dfrac{1}{n}-\dfrac{1}{n+1}\) 

Chúc bạn học tốt!

Ai tick mk lên 30 -> 40 điểm mk tick cho cả tháng 

\(A=10^2-\left(5^2.4-4^3.3\right)+2^3\)

\(A=10^2-\left(100-4^3.3\right)+2^3\)

\(A=10^2-\left(100-192\right)+2^3\)

\(A=10^2-\left(-92\right)+2^3\)

\(A=192+2^3\)

\(A=200\)

\(A=\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+\frac{1}{1+2+3+4+5}\)

\(A=\frac{1}{\left(1+2\right).2:2}+\frac{1}{\left(1+3\right).3:2}+\frac{1}{\left(1+4\right).4:2}+\frac{1}{\left(1+5\right).5:2}\)

\(A=\frac{2}{2.3}+\frac{2}{3.4}+\frac{2}{4.5}+\frac{2}{5.6}\)

\(A=2\left(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}\right)\)

\(A=2\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\right)\)

\(A=2\left(\frac{1}{2}-\frac{1}{6}\right)\)

\(A=2.\frac{1}{3}=\frac{2}{3}\)