Question

[Nguyễn văn Huy]

tim x , biet:\(\left(\frac{1}{4.7}+\frac{1}{7.10}+...+\frac{1}{37.40}\right)-x=\frac{4}{5}\)

Answer 1

[Akame]

=>[(1/4-1/7+1/7-1/10+...+1/37-1/40):3]-x=4/5

=>[(1/4-1/40):3]-x=4/5

=>(9/40:3)-x=4/5

=>3/40-x=4/5

=>x=3/40-4/5

=>x=-29/40

K nhe bn. Chinh xac roi day