x + 4/5*9 + 4/9*13 + 4/13*17 + ... + 4/41*45 = 1
<=> x + 4/5*9 + 4/9*13 + 4/13*17 + ... + 4/41*45 = 1
<=> x + (9-5)/5*9 + (13-9)/9*13 + (17-13)/13*17 + ... + (45 - 41)/41*45 = 1
<=> x + 9/5*9 - 5/5*9 + 13/9*13 - 9/9*13 + 17/13*17 - 13/13*17 +...+ 45/41*45 - 41/41*45 = 1
<=> x + 1/5 - 1/9 + 1/9 - 1/13 + 1/13 - 1/17 + ... + 1/41 - 1/45 = 1
<=> x + 1/5 - 1/45 = 1
<=> x = 1 - 1/5 + 1/45 = 37/45
Vậy x = 37/45

loi giai lien thien

Tìm x, biết: x + 4/5*9 + 4/9*13 + 4/13*17 + ... + 4/41*45 = 1
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x + 4/5*9 + 4/9*13 + 4/13*17 + ... + 4/41*45 = 1
=> x + (1/5 - 1/9) + (1/9 - 1/13) + (1/13 - 1/17) + ... + (1/41 - 1/45) = 1
=> x + 1/5 - 1/45 = 1
=> x - 1/45 = 1 - 1/5
=> x = 1 - 1/5 + 1/45
=> x= 45/45 - 9/45 + 1/45
=> x = (45 - 9 + 1)/45
=> x = 37/45
Vậy x = 37/45
vô trang mình 5 sao nha

x<0
qua vo van

6:2.(3-1):3=??
vo van 

@ ngococtram ban hoc quy tac nhan.hay lop 5 ko biet