a=(1+1/2) x ( 1+1/3) x (1+1/4) x (1+1/5) x (1+1/6)
giúp mik zới
cú t ccau oiii ét ô ét giải giúp t bài này zới
4,7 : 0,25 + 5,3 x 4
3x ( a - 2) +150 = 240
1/9 + a + 7/12 = 17/18
( 1/2 x 1/3 + 1/3 x 1/4 + 1/4 x 1/5 + 1/5 x 1/6 + 1/6 x 1/7 + 1/7 x 1/8 ) x a = 9/16
\(4,7\div0,25+5,3\times4\)
\(=18,8+21,2\)
\(=40\)
\(3\times\left(a-2\right)+150=240\)
\(3\times\left(a-2\right)=90\)
\(a-2=30\)
\(a=32\)
\(\dfrac{1}{9}+a+\dfrac{7}{12}=\dfrac{17}{18}\)
\(\dfrac{1}{9}+a=\dfrac{13}{36}\)
\(a=\dfrac{1}{4}\)
\(\left(\dfrac{1}{2}\times\dfrac{1}{3}+\dfrac{1}{3}\times\dfrac{1}{4}+\dfrac{1}{4}\times\dfrac{1}{5}+\dfrac{1}{5}\times\dfrac{1}{6}+\dfrac{1}{6}\times\dfrac{1}{7}+\dfrac{1}{7}\times\dfrac{1}{8}\right)\times a=\dfrac{9}{16}\)
\(\left(\dfrac{1}{2\times3}+\dfrac{1}{3\times4}+\dfrac{1}{4\times5}+\dfrac{1}{5\times6}+\dfrac{1}{6\times7}+\dfrac{1}{7\times8}\right)\times a=\dfrac{9}{16}\)
\(\left(\dfrac{1}{2}-\dfrac{1}{8}\right)\times a=\dfrac{9}{16}\)
\(\dfrac{3}{8}\times a=\dfrac{9}{16}\)
\(a=\dfrac{3}{2}\)
A = 1 + 1 x 2 + 1 x 2 x 3 + 1 x 2 x 3 x 4 + 1 x 2 x 3 x 4 x 5 + ........... + 1 x 2 x 3 x ....... x 100 .
ai giúp zới
1x(1+2+3+4+5+6+7+8+9...+100)= 1x100=100
vậy A= 100
H = [ 1 + 1/ 1 x 3 ] x [ 1 + 1 / 2 x 4 ] x [ 1 + 1 / 3 x 5 ] x [ 1 + 1 x 4 x 6 ] x [ 1 + 1/ 5 x 7 ]
giúp mik vs mik cảm ơn nhiều mik tick cho............ giúp vs
1.tính 3/9 + 5/6 x 2/3
2.tính bằng cách thuận tiện nhất A=( 1 - 1/2 ) x ( 1 - 1/3 ) x ( 1 - 1/4 ) x ( 1 - 1/5 )
trình bày ra giúp mik nha
Ai nhanh với đúng mik tích
(1-1/2)×(1-1/3)×(1-1/4)×(1-1/5)×1-1/6=1/2×2/3×3/4×4/5×5/6=1/6
a] 1/3 + 4/3 x 1/2
b] x : 2/5 = 1/6 + 2/3
Chi tiết giúp mik nha
1/2+2/3 = 3/3 = 1
x : 2/5 = 5/6
x = 5/6x2/5
x = 1/3
\(\dfrac{1}{2}+\dfrac{2}{3}=\dfrac{3}{3}=1\)
x : \(\dfrac{2}{5}\) = \(\dfrac{5}{6}\)
x = \(\dfrac{5}{6}\)x\(\dfrac{2}{5}\)
x = \(\dfrac{1}{3}\)
a)x-1/9=8/3
b)x/5=5/6+-13/30
c)3/4+1/4:x=-1
d)1/4-5/18<x/36<-8/5+1(x(-z)
giúp mik với
Bạn ghi đề bài phần d) rõ ra hơn nha .
Mn giúp mik zới:>
tính giá trị biểu thức sau: (-x^2y^5)^2:(-x^2y^5) tại x=1/2 và y=-1
\(\left(-x^2y^5\right)^2:\left(-x^2y^5\right)=-x^2y^5=-\left(\dfrac{1}{2}\right)^2.\left(-1\right)^5=-\dfrac{1}{4}.\left(-1\right)=\dfrac{1}{4}\)
[ 1/3 + 1/5 ] + [ 1/6 - 1/5 ]
3/16 x 7/5 + 3/5 x 9/16
1/1x2 + 1/2x3 + 1/ 3x4 + ...... + 1/2020x2021
1/1x3 + 1/3x5 + 1/5x7 + ..... + 1/2021 x 2023
3/2 x 1/7 x 5/4 + 15/2 x 6/7 x 1/4
NHỜCÁC BN LM GIÚP MIK GẤP CHIỀU NAY MIK CẦN ÒI !!!!!~~~
TÍNH BẰNG CÁCH NHANH NHẤT NHA CÁC BN
a) \(\left(\frac{1}{3}+\frac{1}{5}\right)+\left(\frac{1}{6}-\frac{1}{5}\right)=\left(\frac{1}{3}+\frac{1}{6}\right)+\left(\frac{1}{5}-\frac{1}{5}\right)=\frac{1}{2}\)
b) \(\frac{3}{16}\times\frac{7}{5}+\frac{3}{5}\times\frac{9}{16}=\frac{21}{80}+\frac{27}{80}=\frac{48}{80}=\frac{3}{5}\)
c) \(\frac{1}{1\times2}+\frac{1}{2\times3}+...+\frac{1}{2020\times2021}=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{2020}-\frac{1}{2021}\)
\(=1-\frac{1}{2021}=\frac{2020}{2021}\)
d) \(\frac{1}{1\times3}+\frac{1}{3\times5}+...+\frac{1}{2021\times2023}=\frac{1}{2}\times\left(\frac{2}{1\times3}+\frac{2}{3\times5}+...+\frac{2}{2021\times2023}\right)\)
\(=\frac{1}{2}\times\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{2021}-\frac{1}{2023}\right)\)
\(=\frac{1}{2}\times\left(1-\frac{1}{2023}\right)=\frac{1}{2}\times\frac{2022}{2023}=\frac{1011}{2023}\)
e) \(\frac{3}{2}\times\frac{1}{7}\times\frac{5}{4}+\frac{15}{2}\times\frac{6}{7}\times\frac{1}{4}==\frac{15}{56}+\frac{80}{56}=\frac{95}{56}\)
1\2 x 1\3 + 1\3 x 1\4 + 1\4 x 1\5 x 1\6 x 1\6 + 1\6 x 1\7 + 1\7 x 1\8 + 1\8 x 1\9 + 1\9 x 1\10
giúp mik nha (^.^)
\(\frac{1}{2}\times\frac{1}{3}\times.........\times\frac{1}{10}=\frac{1}{2\times3}+......+\frac{1}{9\times10}\)
\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-..........-\frac{1}{10}=\frac{1}{2}-\frac{1}{10}=\frac{2}{5}\)