Gọi A=4/5.9+4/9.13+4/13.17+...+4/41.45
4.A=4.4/5.9+4.4/9.13+...+4.4/41.45
A=4/5-4/9+4/9-4/13+...+4/41-4/45
A=4/5-4/45
A=32/45
Vậy 4/5.9+4/9.13+...+4/41.45=32/45
Mình ko biết nha.Mình cũng ko biết làm
tìm x biết
a,x\2008 - 1\10 -1\15 -1\21 - ...-1\120 = 5\8
b,7\x + 4\5*9 + 4\9*13 + 4\ 13*17 +...+4\41*45=29\45
tìm x: 7/x + 4/5*9 + 4/9*13 +...+ 4/41*45=29/45
Tìm x
a)7/x+4/5×9+4/9×13+...+4/41×45=29/93
b)x+2/1×3+2/3×5+...+2/49×51=5/17
c)1/4-1/2×4-1/4×6-...-1/2x(2x+2)=23/176
a)7/x+4/5×9+4/9×13+...+4/41×45=29/93
b)x+2/1×3+2/3×5+...+2/49×51=5/17
c)1/4-1/2×4-1/4×6-...-1/2x(2x+2)=23/176
Tìm x
Bài 1:tính
a)-1+4-5+8-9+12-...-53+56
b)-1+5-9+13-...-41+45
c)(1-3+5-7+...+17)+(-2+4-6+...-18)
giải giùm mk nha
g) (-457) + (-123) + 23 +237
h) 1 - 3 + 5 - 7 + ... + 41 - 43 + 45 - 47
i) 173 + (-46) + (-54) + (+27)+ (-19)
k) (-52) + 13 + 49 + (-15) + (-36) + 82
l) 3 + (-5) + 7 + (-9) + 11 + (-13) + 15 + (-17)
m) 1 + (-2) + 3 + (-4) + ... + 2001 + (-2002) + 2003
n) (-51) + (-53) + (-55) + ... + (-97) + (-99)
o) (-62) + (+1523) + (-38) + (-2523)+ (-92)
a) 92/9 + 13/5 - 56/9
b) 58/7 - (31/9 + 30/7)
c) 2/3 + 1/3 x 9/4 - 13/12
d) 41/8 - 7/4 : 11/5
e) 478/19 : 5/4 - 668/19 : 5/4
f) 32/21 x 49/45 : 16/22 x 15/33
g) 2020x2018+9 / 2019x2020-2011.
Giup minh voi minh dang can gap!!!
9/10 - 13/75 - 1/6
2/15 - 2/65 - 4/39
31/23 - (7/32 + 8/23)
(1/3+12/67+13/41) - (79/67 - 28/41)
38/45 - (8/45 - 17/51- 3/11)
a) 21/47 + 9/45 +26/47 + 4/5
= (21/47 + 26/47) + (9/45 + 4/5)
=1+1 = 2
b) 15/12 + 5/13 - 3/12 - 18/13
= (15/12 - 3/12) + (18/13 - 5/13)
=1+1 = 2
c) 13/25 + 6/41 - 38/25 + 35/41 - 1/2
= (38/25 - 13/25) + (35/41 + 6/41) + 1/2
= 1+1 + 1/2 = 5/2
d) 27/23 + 5/21 - 4/23 + 6/21 + 1/2
= (27/23 - 4/23) + (6/21 - 5/21) + 1/2
= ..........................
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