a,A= (-1)*(-2)*(-3)*(-4)*...*(-2019)
b,B=1/1*2+1/2*3+1/3*4+...+1/98*99+1/99*100
c,C=2^10*13+2^10*65/2^8*104
d,D=70*(131313/565656+131313/727272+131313/909090)
tinh nhanh
a) A=(-1).(-1)^2.(-1)^3.(-1)^4....(-1)^2010.(-1)^2011
b) B=70.(131313/565656+131313/727272+131313/909090)
d)D= -1/20+ -1/30+ -1/42+ -1/56+ -1/72+ -1/90
e) E= 5/2.1+4/1.11+3/11.2+1/2.15+13/15.4
Các bạn giúp mình với
Bài 1
A=1×2×3×...×9-1×2×3×...×8-1×2×3...8×8
B=(3×4×2mũ16) mũ 2
C=70×(131313/565656+131313/727272+131313/909090)
D thực hiện phép tính : B=1/4×9+1/9×14+1/14×19+...+1/64×69
Bài 2
C)(2.x-15) mũ 5=(2.x-15) mũ 3
Câu 1.Tính giá trị các biểu thức sau :
a) A = (-1).(-1)2.(-1)3.(-1)4...(-1)2010.(-1)2011
b) B = 70.(131313 : 565656 + 131313 : 727272 + 131313 : 909090)
c) C = 2a : 3b + 3b : 4c + 4c : 5d + 5d : 2a biết 2a : 3b = 3b : 4c = 4c : 5d = 5d :2a
\(C=70.\left(\dfrac{131313}{565656}+\dfrac{131313}{727272}+\dfrac{131313}{9909090}\right)\)
\(B=\dfrac{1}{4.9}+\dfrac{1}{9.14}+\dfrac{1}{14.19}+......+\dfrac{1}{ }64.69\)
\(A=\dfrac{2}{1.4}+\dfrac{2}{4.7}+\dfrac{2}{7.10}+....+\dfrac{2}{97.100}\)
b: Ta có: \(B=\dfrac{1}{4\cdot9}+\dfrac{1}{9\cdot14}+...+\dfrac{1}{64\cdot69}\)
\(=\dfrac{1}{5}\left(\dfrac{5}{4\cdot9}+\dfrac{5}{9\cdot14}+...+\dfrac{5}{64\cdot69}\right)\)
\(=\dfrac{1}{5}\left(\dfrac{1}{4}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{14}+...+\dfrac{1}{64}-\dfrac{1}{69}\right)\)
\(=\dfrac{1}{5}\cdot\dfrac{65}{4\cdot69}\)
\(=\dfrac{13}{276}\)
\(A=\dfrac{2}{1\cdot4}+\dfrac{2}{4\cdot7}+...+\dfrac{2}{97\cdot100}\\ A=\dfrac{2}{3}\left(\dfrac{3}{1\cdot4}+\dfrac{3}{4\cdot7}+...+\dfrac{3}{97\cdot100}\right)\\ A=\dfrac{2}{3}\left(1-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+...+\dfrac{1}{97}-\dfrac{1}{100}\right)\\ A=\dfrac{2}{3}\left(1-\dfrac{1}{100}\right)=\dfrac{2}{3}\cdot\dfrac{99}{100}=\dfrac{33}{50}\\ B=\dfrac{1}{4\cdot9}+\dfrac{1}{9\cdot14}+...+\dfrac{1}{64\cdot69}\\ B=\dfrac{1}{5}\left(\dfrac{5}{4\cdot9}+\dfrac{5}{9\cdot14}+...+\dfrac{5}{64\cdot69}\right)\\ B=\dfrac{1}{5}\left(\dfrac{1}{4}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{14}+...+\dfrac{1}{64}-\dfrac{1}{69}\right)\\ B=\dfrac{1}{5}\left(\dfrac{1}{4}-\dfrac{1}{69}\right)=\dfrac{1}{5}\cdot\dfrac{65}{276}=\dfrac{13}{276}\)
\(C=70\left(\dfrac{13}{56}+\dfrac{13}{72}+\dfrac{13}{90}\right)=70\cdot13\left(\dfrac{1}{56}+\dfrac{1}{72}+\dfrac{1}{90}\right)\\ C=910\left(\dfrac{1}{7\cdot8}+\dfrac{1}{8\cdot9}+\dfrac{1}{9\cdot10}\right)\\ C=910\left(\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}\right)\\ C=910\left(\dfrac{1}{7}-\dfrac{1}{10}\right)=910\cdot\dfrac{3}{70}=39\)
A, 125% . (\(\frac{-1}{2}^2\)) : (\(1\frac{5}{16}-1,5\)) + \(2019^0\)
B, (15-\(6\frac{13}{18}\)) : 11\(\frac{1}{27}\)- 2\(\frac{1}{8}\): 1\(\frac{11}{40}\)
C, 70 . (\(\frac{131313}{565656}\)+ \(\frac{131313}{727272}\)+ \(\frac{131313}{909090}\))
Giúp mình nhanh thật nhanh nhé mấy bạn <3
B=70.(131313/565656+131313/727272+131313/909090)
\(B=70\cdot\left(\frac{131313}{565656}+\frac{131313}{727272}+\frac{131313}{909090}\right)\)
\(B=70\cdot\left(\frac{13}{56}+\frac{13}{72}+\frac{13}{90}\right)\)
\(B=70\cdot\frac{39}{70}\)
\(B=39\)
Vậy B = 39
B=\(70\times\left(\frac{131313}{565656}+\frac{131313}{727272}+\frac{131313}{909090}\right)\)
B=\(70\times\left(\frac{13}{56}+\frac{13}{72}+\frac{13}{90}\right)\)
B=\(70\times\frac{39}{70}\)
B=\(39\)
Nếu mk làm sai thì xin lỗi bạn nhiều nha
Thực hiện phép tính để tính giá trị các biểu thức sau:
\(a,A=\left(\frac{136}{15}-\frac{28}{5}+\frac{62}{10}\right).\frac{21}{24}\)
\(b,B=70.\left(\frac{131313}{565656}+\frac{131313}{727272}+\frac{131313}{909090}\right)\)
\(c,C=\frac{5}{2.1}+\frac{4}{1.11}+\frac{3}{11.2}+\frac{1}{2.15}+\frac{13}{15.4}\)
a) A= ( 136/15 - 28/5 + 62/10) .21/24
A= (136/15 - 84/15 + 93/15) . 7/8
A= 145/15. 7/8
A= 203/24
b) B= 70 .( 131313.565656 + 131313/727272 + 131313/ 909090)
= 70. ( 13/56+ 13/72 + 13/90)
= 70 . 39/70
= 39
trả lời khẩn cấp nha!!!
tính các giá trị biểu thức sau
a)A= (-1).(-1)2.(-1)3.(-1)4.(-1)5.(-1)6.(-1)7....(-1)2010.(-1)2011
b) B= 70 . (131313/565656+ 131313/727272+131313/909090)
c) C= 2a/3b+3b/4c+4c/5d+5d/2a biết 2a/3b= 3b/4c=4c/5d=5d/2a
Tính giá trị biểu thức:
\(a,A=\left(-1\right).\left(-1\right)^2.\left(-1^3\right).\left(-1\right)^4...........\left(-1\right)^{2016}.\left(-1\right)^{2017}\)
\(b,B=70.\left(\frac{131313}{565656}+\frac{131313}{727272}+\frac{131313}{909090}\right)\)
\(c,C=\frac{2a}{3b}+\frac{3b}{4c}+\frac{4c}{5d}+\frac{5d}{2a}\)
biết\(\frac{2a}{3b}=\frac{3b}{4c}=\frac{4c}{5d}=\frac{5d}{2a}\)
Câu hỏi của ✨♔♕ Saiko ♕♔✨ - Toán lớp 6 - Học toán với OnlineMath