b) B = 2 5 . 8 + 2 8 . 11 + 2 11 . 14 + . . . + 2 92 . 95
Câu 1:thực hiện phép tính
a)(-5)+11+17+(-3)
b)17/8-5/8+(-7)/8+11/8
c)4/11+(-5)/13+7/11+(-8)/13
d)(-9)/23.(5/3)^2+1/46.(-2)^2
a; (-5) + 11 + 17 + (-3)
= - 5 + 11 + 17 - 3
= - (5 + 3) + (11 + 17)
= - 8 + 28
= 20
b; \(\dfrac{17}{8}\) - \(\dfrac{5}{8}\) + \(\dfrac{-7}{8}\) + \(\dfrac{11}{8}\)
= \(\dfrac{12}{8}\) - \(\dfrac{7}{8}\) + \(\dfrac{11}{8}\)
= \(\dfrac{5}{8}\) + \(\dfrac{11}{8}\)
= \(\dfrac{16}{8}\)
= 2
b,8/5 11/8 16/13 14/11 21/18 5/2
Bạn cần viết đề bằng công thức toán để được hỗ trợ tốt hơn. Viết như thế này rất khó dịch bạn nhé.
B = \(\dfrac{5}{2}\)+\(\dfrac{6}{11}\)+\(\dfrac{3}{8}\)+\(\dfrac{7}{2}\)+\(\dfrac{6}{8}\)+\(\dfrac{5}{11}\)
tính nhanh
Mình nghĩ đề là : 2/8 sẽ hay hơn.
\(B=\dfrac{5}{2}+\dfrac{6}{11}+\dfrac{2}{8}+\dfrac{7}{2}+\dfrac{6}{8}+\dfrac{5}{11}\)
\(=\left(\dfrac{5}{2}+\dfrac{7}{2}\right)+\left(\dfrac{6}{11}+\dfrac{5}{11}\right)+\left(\dfrac{2}{8}+\dfrac{6}{8}\right)\)
\(=6+1+1=8\)
\(B=\dfrac{5}{2}+\dfrac{6}{11}+\dfrac{3}{8}+\dfrac{7}{2}+\dfrac{6}{8}+\dfrac{5}{11}\)
\(B=\left(\dfrac{5}{2}+\dfrac{7}{2}\right)+\left(\dfrac{6}{11}+\dfrac{5}{11}\right)+\left(\dfrac{3}{8}+\dfrac{6}{8}\right)\)
\(B=6+1+1,125\)
\(B=8,125\)
A=-1/2011-5/112-5/113-8/118
B=-1/2011-8/112-5/113-5/118
giúp mình với mình k cho
a) 5/11 x 3/7 +5/11 x 4/7 -3/11
b) -13/8 + 5/8 + 7/5 - 2/7 + 1/2
A)\(\frac{5x-3}{11}\)
B)-0,9
mình hơi bận nên ghi mỗi lời giải mong các bạn thông cảm.
a, 5/11 x 3/7 + 5/11 x 4/7 - 3/11
= 5/11 x ( 3/7 + 4/7 ) - 3/11
= 5/11 x 1 -3/11
=2/11
b,-13/8 + 5/8 + 7/5 - 2/7 + 1/2
= ( -13/8 + 5/8 ) +7/5 - 2/7 + 1/2
= -1 + 7/5 - 2/7 +1/2
= 2/5 - 7/5 + 1/2
= -1 +1/2
= -1/2
tính bằng cách thuận tiện
a] 5/6 : 8/9 -3/4 : 8/9
b] 1/11 cộng 2/11 cộng 3/11cộng 4/11 cộng 5/11 cộng 5/11 cộng 7/11 cộng 8/11 cộng 9/11 cộng 10/11
Bài 1:
a) 8/7 - 5/11 : 8 b) 1 + 2/9 : 7/3 - 10/7 c) 11/3 - 2 : 7/3 + 4
Bài 2:
a) 9/4 - x = 5/11 : 1/2 b) 2/9 : x = 7/3 - 10/7
Bài 3:
\(\dfrac{1999x1998-1}{1997x1999+1998}\)
1:
a: =8/7-5/88=669/616
b: \(=1+\dfrac{2}{9}\cdot\dfrac{3}{7}-\dfrac{10}{7}=1+\dfrac{2}{21}-\dfrac{10}{7}\)
\(=\dfrac{21+2-30}{21}=\dfrac{-7}{21}=\dfrac{-1}{3}\)
c: \(=\dfrac{11}{3}-\dfrac{6}{7}+4=\dfrac{77-18+84}{21}=\dfrac{143}{21}\)
Bài 2:
a: =>9/4-x=5/11*2=10/11
=>x=9/4-10/11=59/44
b: =>2/9:x=19/21
=>x=2/9:19/21=14/57
Bài 1 :Tính nhanh
A=2/7+-3/8+11/7+1/3+1/7+5/-8
B=-3/8+12/25+5/-8+2/-5+13/25
\(A=\left(\dfrac{2}{7}+\dfrac{11}{7}+\dfrac{1}{7}\right)+\left(\dfrac{-3}{8}+\dfrac{-5}{8}\right)+\dfrac{1}{3}=2-1+\dfrac{1}{3}=1+\dfrac{1}{3}=\dfrac{4}{3}\)
\(B=\dfrac{-3}{8}+\dfrac{12}{25}+\dfrac{-5}{8}+\dfrac{-2}{5}+\dfrac{13}{25}=1+1-\dfrac{5}{8}=-\dfrac{5}{8}\)
Bài 1 :Tính nhanh
A=2/7+-3/8+11/7+1/3+1/7+5/-8
B=-3/8+12/25+5/-8+2/-5+13/25
A=2/7+-3/8+11/7+1/3+1/7+5/-8
=(2/7+11/7+1/7)+(-3/8-5/8)+1/3
=2+(-1)+1/3 =1+1/3 =4/3
B=-3/8+12/25+5/-8+2/-5+13/25
=(-3/8-5/8)+(12/25+13/25)-5/8
=-1+1-5/8= -5/8
a) 5/8 + 3/8 : 2/3 b) 3/5 x 5/7 + 1/11
a)5/8 + 3/8 : 2/3
=5/8 + 9/16
=19/16
b)3/5 x 5/7 +1/11
=3/7+ 1/11
=40/77