x-4/5*9-4/9*13-4/13*17-.....-4/41*45=37/45
Tìm x biết
A, x/4 - 3/7 + 2/5 = 31/140
B, 5/12 + 5/x - 1/8 = 1/2
C, x + 4/5×9 + 4/9×13 + 4/13×17 +.....+ 4/41×45 = -37/45
4/5×9+4/9×13+4/13×17+...+4/41×45 = ?
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
tính nhanh 4/1 x 5+ 4/5 x 9 + 4/9 x 13+⋯+4/41 x 45 + 4/45 x 49
tìm x: 7/x + 4/5*9 + 4/9*13 +...+ 4/41*45=29/45
\(\frac{7}{x}+\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{41.45}=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}+\left(\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{41.45}\right)=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}+\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+...+\frac{1}{41}-\frac{1}{45}\right)=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}+\left(\frac{1}{5}-\frac{1}{45}\right)=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}+\frac{8}{45}=\frac{29}{45}\)
\(\Rightarrow\frac{7}{x}=\frac{29}{45}-\frac{8}{45}\)
\(\Rightarrow\frac{7}{x}=\frac{7}{15}\)
\(\Rightarrow x=15\)
Vậy x = 15
_Chúc bạn học tốt_
Tìm x:7/x +4/5\(\times\)9+4/9\(\times\)13+4/13\(\times\)17+....+4/41\(\times\)=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
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!!!
58/7 - (31/9 + 30/7)
= 58/7 - 31/9 - 30/7
= (58/7 - 30/7) - 31/9
= 28/7- 31/9
= 4 - 31/9 = 36/9 - 31/9
= 5/9
478/19÷(-5/4)-668/19÷(-5/4)
=(478/19-668/19):(-5/4)
=-10 . (-4/5)
=8