\(-\frac{1}{6},\frac{1}{-9},\frac{-1}{12}\)giúp mik
cho A=\(\frac{1}{3}.\frac{4}{6}.\frac{7}{9}.\frac{10}{12}.....\frac{208}{210}\)
cmr: A<\(\frac{1}{25}\)
giúp mik với mik cần gấp
Tính tổng :
\(\frac{3}{1.4}+\frac{6}{4.10}+\frac{9}{10.19}+\frac{12}{19.31}+\frac{15}{31.46} +\frac{18}{46.64}\)
các bn ơi giúp mik nhé mik cần gấp lắm làm ơn!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1
\(\frac{3}{1.4}+\frac{6}{4.10}+\frac{9}{10.19}+\frac{12}{19.31}+\frac{15}{31.46}+\frac{18}{46.64}\)
\(=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{10}+\frac{1}{10}-\frac{1}{19}+\frac{1}{19}-\frac{1}{31}+\frac{1}{31}-\frac{1}{46}+\frac{1}{46}-\frac{1}{64}\)
\(=1-\frac{1}{64}=\frac{63}{64}\)
Bạn ko hiểu chỗ nào là phải hỏi mình ngay nhé!
1 Tính
c) \(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+..................+\frac{1}{90}=\)
giúp mik nha, mik kb cho
1/3 + 1/6 + 1/9 + 1/18
= 6/18 + 3/18 + 2/18 + 1/18
= 12/18
= 2/3
b) 42/24 - 10/8 - 2/4
= 42/24 - 30/24 - 12/24
= 0
=1/2x3 + 1/3x4 + 1/ 4x5 +.............+1/9x10
=3-2/2x3 + 4-3/3x4 + 5-4/4x5 + ..........+ 10-9/9x10
=3/2x3 - 2/3x2 + 4/3x4 - 3/4x3 + 5/4x5 - 4/4x5 + .............+10/9x10 - 9 /10x9
=1/2-1/3+1/3-1/4+1/4-1/5+.........................+1/9-1/10
=1/2-1/10
=2/5
\(\frac{1}{9}+\frac{8}{9}=??\)
\(\frac{1}{12}+\frac{2}{12}+\frac{6}{12}+\frac{3}{12}=???\)
~~~ GIẢI CỤ THỂ TỪNG CHI TIẾT NHA ~~~
_Mik sẽ kiểm tra ai đúng nhất thì mik sẽ cho 4 tíck_
> 12 phút sau mik sẽ giải bài <
\(\frac{1}{9}+\frac{8}{9}=\frac{1+8}{9}=\frac{9}{9}=1\)
\(\frac{1}{12}+\frac{2}{12}+\frac{6}{12}+\frac{3}{12}=\frac{1+2+6+3}{12}=\frac{12}{12}=1\)
Chúc bạn học tốt !!
\(\frac{1}{9}\)+\(\frac{8}{9}\)=\(\frac{1+8}{9}\)=\(\frac{9}{9}\)=\(1\)
\(\frac{1}{12}\)+\(\frac{2}{12}\)+\(\frac{6}{12}\)+\(\frac{3}{12}\)=\(\frac{1+2+6+3}{12}\)=\(\frac{12}{12}\)=\(1\)
\(\frac{\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{90}}{5+\frac{5}{3}+\frac{5}{6}+\frac{1}{2}+...+\frac{1}{9}}\)
Tính nhanh. M.n giúp dùm nhak. Tks
Tính
a)\(\left(17\frac{13}{15}-3\frac{3}{7}\right)-\left(2\frac{12}{15}-4\right)\)
b) \(\left(3\frac{2}{9}.\frac{15}{23}.1\frac{7}{29}\right):\frac{5}{23}\)
c)\(2\frac{17}{20}-1\frac{11}{5}+6\frac{9}{20}:3\)
giúp mik với ,mik đag cần gấp.Tks
Tìm x:
a, x + 30%x = -1,31
b,\(\left(x-\frac{1}{2}\right):\frac{1}{3}+\frac{5}{7}=9\frac{5}{7}\)
c, \(\frac{1}{2}x-\frac{3}{4}=\frac{14}{9}.\frac{3}{7}\)
d,\(\frac{-5}{6}-x=\frac{7}{12}+\frac{-1}{3}\)
e,\(\frac{x+3}{-15}=\frac{1}{3}\)
f,\(\left(4,5-2x\right).\left(-1\frac{4}{7}\right)=\frac{11}{14}\)
GIÚP MIK LM TRONG TỐI NAY NHA, MAI MIK PHẢI NỘP RỒI
\(a)x+30\%x=-1,31\)
\(\Leftrightarrow x+\frac{3x}{10}=-1,31\)
\(\Leftrightarrow10x+3x=-13,1\)
\(\Leftrightarrow13x=-13,1\Leftrightarrow x=-\frac{131}{130}\)
\(b)\left(x-\frac{1}{2}\right):\frac{1}{3}+\frac{5}{7}=9\frac{5}{7}\)
\(\Leftrightarrow\frac{2x-1}{2}.3+\frac{5}{7}=\frac{68}{7}\)
\(\Leftrightarrow\frac{6x-3}{2}=\frac{63}{7}\)
\(\Leftrightarrow\frac{6x-3}{2}=9\)
\(\Leftrightarrow6x-3=18\)
\(\Leftrightarrow x=\frac{7}{2}\)
\(c)\frac{1}{2}x-\frac{3}{4}=\frac{14}{9}.\frac{3}{7}\)
\(\Leftrightarrow\frac{x}{2}-\frac{3}{4}=\frac{2}{3}\)
\(\Leftrightarrow\frac{x}{2}=\frac{17}{12}\)
\(\Leftrightarrow12x=34\Leftrightarrow x=\frac{17}{6}\)
1. Tìm x thuộc Z biết:
a,\(\frac{-5}{6}.\frac{120}{25}< x< \frac{-7}{15}.\frac{9}{14}\)
b,\(\left(\frac{-5}{3}\right)^3< x< \frac{-24}{35}.\frac{-5}{6}\)
2. Thực hiện phép tính:
a,\(\left(\frac{9}{10}-\frac{15}{16}\right).\left(\frac{5}{12}-\frac{11}{15}-\frac{7}{20}\right)\)
b,\(\frac{-3}{5}+\frac{28}{5}.\left(\frac{43}{56}+\frac{5}{24}-\frac{21}{63}\right)\)
AI GIÚP MIK VỚI,MIK DÂNG CẦN GẤP,SÁNG MAI MIK PHẢI NỘP CHO CÔ RỒI,GIÚP MIK NHA
1)
a)
\(\frac{-5}{6}.\frac{120}{25}< x< \frac{-7}{15}.\frac{9}{14}\)
\(\frac{-1}{1}.\frac{20}{5}< x< \frac{-1}{5}.\frac{3}{2}\)
\(\frac{-20}{5}< x< \frac{-3}{10}\)
\(\frac{-40}{10}< x< \frac{-3}{10}\)
\(\Rightarrow Z\in\left\{-4;-5;-6;-7;-8;-9;-10;...;-39\right\}\)
\(\left(\frac{-5}{3}\right)^3< x< \frac{-24}{35}.\frac{-5}{6}\)
\(\frac{25}{3}< x< \frac{-4}{7}.\frac{1}{1}\)
\(\frac{-25}{3}< x< \frac{-4}{7}\)
\(\frac{-175}{21}< x< \frac{-12}{21}\)
\(\Rightarrow Z\in\left\{-13;-14;-15;-16;...;-174\right\}\)
2)
a)
\(\left(\frac{9}{10}-\frac{15}{16}\right).\left(\frac{5}{12}-\frac{11}{15}-\frac{7}{20}\right)\)
\(=\left(\frac{72}{80}-\frac{75}{80}\right).\left(\frac{25}{60}-\frac{44}{60}-\frac{21}{60}\right)\)
\(=\frac{-3}{80}.\frac{-40}{60}\)
\(=\frac{-1}{-2}.\frac{-1}{-20}\)
\(=\frac{1}{40}\)
tính:
\(\frac{\frac{1}{9}-\frac{5}{6}-4}{\frac{7}{12}-\frac{1}{36}-10}\)
CÁC BN GIAIR GIÙM MIK NHÉ!!!
THANK YOU!!!!!!!!