Tìm x :
a) X x \(\frac{9}{13}\)= \(\frac{5}{6}\) b) \(\frac{7}{9}\)+ \(\frac{5}{x}\)= \(\frac{73}{36}\)
giúp mình vs với !! Mình tick cho
1. Thực hiện phép tính :
\(\frac{-4}{9}.\frac{6}{13}+7\frac{4}{9}-\frac{4}{9}:\frac{13}{7}-5\frac{4}{9}-2\)2
2.Tìm x trong trường hợp sau :
x thuộc Z, 1 < (hoặc bằng) \(\frac{x}{5}\) < 0
Mọi người giúp mình nhé :D Nhớ ghi cách làm nữa nha rồi mình tick cho ;P
Tìm x biết
a) \(\frac{x+5}{95}+\frac{x+10}{90}+\frac{x+15}{85}+\frac{x+20}{80}=-4\)
b) \(\frac{x-13}{87}+\frac{x-27}{73}+\frac{x-67}{33}+\frac{x-73}{27}=4\)
Giúp mình với !!!!!!!!!!!
Đúng;cách giải rõ ràng sẽ tick
a) (x + 5) / 95 + (x +10)/90 + (x + 15)/85 + (x + 20)/80 = -4
<=> (x + 5)/95 + (x + 5)/90 + 5/90 + (x + 5)/85 + 10/85+ (x + 5)/80 + 15/80 = -4
<=> (x + 5)(1/95+1/90+1/85+1/80) =-4 -5/90-10/85-15/85
<=> (x + 5)(1/95+1/90+1/85+1/80)= -1-(1 + 5/90 )-(1 + 10/85) - (1 + 15/80)
<=>(x + 5)(1/95+1/90+1/85+1/80) = -1 - 95/90 - 95/85 - 95/80
<=>(x + 5)(1/95+1/90+1/85+1/80) = -95 (1/95+1/90+1/85+1/80)
<=> x + 5 = -95 => x = -100
b) Làm tương tự phần a => Kết quả x = 100
Bài 1: tính nhanh
b) B= \(\frac{1}{5}-\frac{3}{7}+\frac{5}{9}-\frac{2}{11}+\frac{7}{13}-\frac{9}{16}-\frac{7}{13}+\frac{2}{12}-\frac{5}{9}+\frac{3}{7}-\frac{1}{5}\)\(-\frac{1}{5}\)
giải nhanh giúp mình với mình tick cho cảm ơn
\(B=\frac{1}{5}-\frac{3}{7}+\frac{5}{9}-\frac{2}{11}+\frac{7}{13}-\frac{9}{16}-\frac{7}{13}+\frac{2}{12}-\frac{5}{9}+\frac{3}{7}-\frac{1}{5}-\frac{1}{5}\)
\(B=\left(\frac{1}{5}-\frac{1}{5}\right)-\left(\frac{3}{7}-\frac{3}{7}\right)+\left(\frac{5}{9}-\frac{5}{9}\right)+\left(\frac{7}{13}-\frac{7}{13}\right)-\frac{2}{11}+\frac{2}{12}-\frac{9}{16}-\frac{1}{5}\)
\(B=0-0+0+0-\frac{2}{11}+\frac{2}{12}-\frac{9}{16}-\frac{1}{5}\)
\(B=\frac{-2}{11}+\frac{2}{12}-\frac{9}{16}-\frac{1}{5}\)
Đến đây chỉ còn cách quy đồng thôi
Giúp mình nhé : Tính bằng 2 cách :
\(a,\left(\frac{6}{11}+\frac{5}{11}\right)x\frac{3}{7}\)
\(b,\frac{3}{5}x\frac{7}{9}+\frac{3}{5}x\frac{2}{9}\)
\(a,\left(\frac{6}{11}+\frac{5}{11}\right)\times\frac{3}{7}\)
Cách 1: \(\left(\frac{6}{11}+\frac{5}{11}\right)\times\frac{3}{7}=1\times\frac{3}{7}=\frac{10}{7}\)
Cách 2: \(\left(\frac{6}{11}+\frac{5}{11}\right)\times\frac{3}{7}=\frac{6}{11}\times\frac{3}{7}+\frac{5}{11}\times\frac{3}{7}=\frac{18}{77}+\frac{15}{77}=\frac{33}{77}=\frac{3}{7}\)
\(b,\frac{3}{5}\times\frac{7}{9}+\frac{3}{5}\times\frac{2}{9}\)
Cách 1: \(\frac{3}{5}\times\frac{7}{9}+\frac{3}{5}\times\frac{2}{9}=\frac{7}{15}+\frac{2}{15}=\frac{9}{15}\)
Cách 2: \(\frac{3}{5}\times\frac{7}{9}+\frac{3}{5}\times\frac{2}{9}=\frac{3}{5}\times1=\frac{3}{5}\)
P/s: Ý B có vấn đề thì phải
\(a,\left(\frac{6}{11}+\frac{5}{11}\right)x\frac{3}{7}\)
\(=\frac{11}{11}=1x\frac{3}{7}\)
\(=\frac{3}{7}\)
cach 2
\(\frac{6}{11}x\frac{3}{7}+\frac{5}{11}x\frac{3}{7}\)
\(=\frac{18}{77}+\frac{15}{77}\)
\(=\frac{33}{77}=\frac{3}{7}\)
\(b,\frac{3}{5}x\frac{7}{9}+\frac{3}{5}x\frac{2}{9}\)
\(=\frac{21}{45}+\frac{6}{45}\)
\(=\frac{27}{45}=\frac{3}{5}\)
cách 2 :
\(\frac{3}{5}x\left(\frac{7}{9}+\frac{2}{9}\right)\)
\(=\frac{3}{5}x\frac{9}{9}\)
\(=\frac{27}{45}=\frac{3}{5}\)
A, c1 | ( 6/11 + 5/11 ) x 3/7 = 1 x 3/7 = 3/7
c2 | ( 6/11 + 5/11 ) x 3/7 = 3/7 x 6/11 + 3/7 x 5/11 = 18/77 + 15/77 = 33/77 = 3/7
B, c1 | 3/5 x 7/9 + 3/5 x 2/9 = 3/5 x ( 7/9 + 2/9 ) = 3/5 x 1 = 3/5
c2 | 3/5 x 7/9 + 3/5 x 2/9 = 7/15 + 2/15 = 9/15 = 3/5
k cho minh nhe
chuc ban hoc tot
Tìm x biết:
\(x-\frac{20}{11.13}-\frac{20}{13.15}-....-\frac{20}{53.55}=\frac{3}{11}\)
\(\frac{1}{21}+\frac{1}{28}+\frac{1}{36}+....+\frac{2}{x.\left(x+1\right)}=\frac{2}{9}\)
giúp mình với mình tick cho!
Ta có: \(x-\frac{20}{11\cdot13}-\frac{20}{13\cdot15}-...-\frac{20}{53\cdot55}=\frac{3}{11}\)
\(\Leftrightarrow x-10\cdot\left(\frac{2}{11\cdot13}+\frac{2}{13\cdot15}+...+\frac{2}{53\cdot55}\right)=\frac{3}{11}\)
\(\Leftrightarrow x-10\cdot\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+...+\frac{1}{53}-\frac{1}{55}\right)=\frac{3}{11}\)
\(\Leftrightarrow x-10\cdot\left(\frac{1}{11}-\frac{1}{55}\right)=\frac{3}{11}\)
\(\Leftrightarrow x-10\cdot\frac{4}{55}=\frac{3}{11}\)
\(\Leftrightarrow x-\frac{8}{11}=\frac{3}{11}\)
\(\Leftrightarrow x=\frac{3}{11}+\frac{8}{11}\)
\(\Leftrightarrow x=1\)
Vậy \(x=1\)thỏa mãn đề.
Tìm x, biết:
a) ( x - 15 ) : 5 + 22 = 24
b) | x + 7 | = 15 - ( -4 )
c) \(\left(x-\frac{1}{2}\right)\div\frac{1}{3}+\frac{5}{7}=9\frac{5}{7}\)
giúp mình với m.n, mình cần gấp
a, (x-15):5+22=24
( x - 15 ) : 5 = 2
x-15 = 10
x = 25
Tìm x: ( ai làm xong trước, mình sẽ tick cho )
\(\frac{x}{-2}=\frac{-8}{x}\)\(\frac{-5}{x}=\frac{20}{28}\)\(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)\(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{36}{48}\)\(\frac{3}{x-5}=\frac{-4}{x+2}\)1.Vì \(\frac{x}{-2}=\frac{-8}{x}\Rightarrow-2.\left(-8\right)=x.x\)
\(16=x.x\)hay \(4^2=x^2\Rightarrow x=4\)
2. Rút gọn : \(\frac{20}{28}=\frac{5}{7}=\frac{-5}{-7}\)
\(\Rightarrow x=-7\)
3. \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)
\(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)
Mà \(\frac{8}{7}+\frac{11}{5}=\frac{502}{35}\)
\(\Rightarrow x=\frac{234}{35}\)
1) \(\frac{x}{-2}=\frac{-8}{x}\)
\(\Rightarrow x\times x=\left(-2\right)\times\left(-8\right)\)
\(\Rightarrow x^2=16\)
\(\Rightarrow\orbr{\begin{cases}x^2=4^2\\x^2=\left(-4\right)^2\end{cases}\Rightarrow}\orbr{\begin{cases}x=4\\x=-4\end{cases}}\)
Vậy x = 4 hoặc x = -4
2) \(\frac{-5}{x}=\frac{20}{28}\)
\(\Rightarrow\frac{-5}{x}=\frac{5}{7}\)
\(\Rightarrow5\times x=\left(-5\right)\times7\)
\(\Rightarrow5\times x=-35\)
\(\Rightarrow x=\left(-35\right):5\)
\(\Rightarrow x=-7\)
Vậy x = -7
3) \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)
\(\Rightarrow\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)
\(\Rightarrow\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)
\(\Rightarrow\frac{x}{2}=\frac{117}{35}\)
\(\Rightarrow35x=117\times2\)
\(\Rightarrow35x=234\)
\(\Rightarrow x=234:35\)
\(\Rightarrow x=\frac{234}{35}\)
Vậy \(x=\frac{234}{35}\)
4) \(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{36}{48}\)
\(\Rightarrow\frac{x}{5}+\frac{9}{2}=\frac{9}{14}\)
\(\Rightarrow\frac{x}{5}=\frac{9}{14}-\frac{9}{2}\)
\(\Rightarrow\frac{x}{5}=\frac{-27}{7}\)
\(\Rightarrow7x=\left(-27\right)\times5\)
\(\Rightarrow7x=-135\)
\(\Rightarrow x=\left(-135\right):7\)
\(\Rightarrow x=\frac{-135}{7}\)
Vậy \(x=\frac{-135}{7}\)
5) \(\frac{3}{x-5}=\frac{-4}{x+2}\)
\(\Rightarrow\frac{3}{x-5}+\frac{4}{x+2}=0\)
\(\Rightarrow3\left(x+2\right)+4\left(x-5\right)=0\)
\(\Rightarrow3x+6+4x-20=0\)
\(\Rightarrow\left(3x+4x\right)+\left(6-20\right)=0\)
\(\Rightarrow7x-14=0\)
\(\Rightarrow7x=14\)
\(\Rightarrow x=14:7\)
\(\Rightarrow x=2\)
Vậy x = 2
_Chúc bạn học tốt_
\(1.\frac{x}{-2}=\frac{-8}{x}\)
\(\Rightarrow x\times x=\left(-8\right)\times\left(-2\right)\)
\(x^2=16\)
\(\Rightarrow x=4\)
Vậy\(x=4\)
\(2.\frac{-5}{x}=\frac{20}{28}\)
\(\frac{-5}{x}=\frac{5}{7}\)
\(\frac{-5}{x}=\frac{-5}{-7}\)
\(\Rightarrow x=-7\)
Vậy\(x=-7\)
\(3.\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)
\(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)
\(\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)
\(\frac{x}{2}=\frac{40+77}{35}\)
\(\frac{x}{2}=\frac{117}{35}\)
\(x\times35=117\times2\)
\(35x=234\)
\(x=\frac{234}{35}\)
Vậy\(x=\frac{234}{35}\)
\(4.\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{36}{48}\)
\(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{3}{4}\)
\(\frac{x}{5}+\frac{9}{2}=\frac{9}{14}\)
\(\frac{x}{5}=\frac{9}{14}-\frac{9}{2}\)
\(\frac{x}{5}=\frac{9}{14}-\frac{63}{14}\)
\(\frac{x}{5}=\frac{-54}{14}\)
\(\frac{x}{5}=\frac{-27}{7}\)
\(7x=\left(-27\right)\times5\)
\(7x=-135\)
\(x=\frac{-135}{7}\)
Vậy\(x=\frac{-135}{7}\)
\(5.\frac{3}{x-5}=\frac{-4}{x+2}\)
\(3\times\left(x+2\right)=\left(-4\right)\times\left(x-5\right)\)
\(3x+6=\left(-4\right)x+20\)
\(3x+4x=20-6\)
\(7x=14\)
\(x=14\div7\)
\(x=2\)
Vậy\(x=2\)
Bài 1: Tìm x
a. \(x-\frac{5}{12}-\frac{4}{9}=\frac{-13}{18}\)
b. \(2-\left(x+\frac{3}{7}\right)=\frac{9}{-21}\)
c. \(x-\frac{-3}{11}=\frac{6}{22}+\frac{1}{4}\)
d. \(\frac{13}{36}-\frac{5}{18}-x=\frac{-11}{9}\)
e. \(x-\frac{3}{7}:\frac{9}{14}=\frac{-17}{3}\)
f. \(\left(x-\frac{1}{2}\right):\frac{3}{11}=\frac{11}{4}\)
g. \(\left(2x+\frac{3}{8}\right).\frac{7}{4}=-\frac{21}{32}\)
h. \(x-\frac{x}{3}=\frac{3}{57}:\frac{12}{19}\)
Vì dài qua cho nên bài 2 mình để riêng nhé
mik ko chép lại đề, mik làm luôn:
a) x - \(\frac{31}{36}=\frac{-13}{38}\)
x = \(\frac{-13}{18}+\frac{31}{36}\)
\(x=\frac{5}{36}\)
b)\(2-x-\frac{3}{7}=\frac{9}{-21}\)
\(\frac{11}{7}-x=\frac{3}{7}\)
x = \(\frac{11}{7}-\frac{3}{7}\)
x = 8/7
c) x + 3/11 = 23/44
x = 23/44 - 3/11
x = 1/4
d) \(\frac{1}{12}-x=\frac{-11}{9}\)
x = \(\frac{1}{12}+\frac{11}{9}\)
x = 47/36
e) \(x-\frac{2}{3}=\frac{-17}{3}\)
x= -17/3 + 2/3
x = -5
f) \(x-\frac{1}{2}=\frac{11}{4}.\frac{3}{11}\)
x - 1/2 = 3/4
x = 3/4 + 1/2
x = 5/4
g) \(2x+\frac{3}{8}=\frac{-21}{32}.\frac{4}{7}\)
2x + 3/8 = -3 / 8
2x = -3/8 - 3/8
2x = -9/8
x = -9/8.1/2
x = -9/16
h) x - \(\frac{x}{3}=\frac{3}{57}.\frac{19}{12}\)
x - \(\frac{x}{3}=\frac{1}{12}\)
x = \(\frac{1}{12}+\frac{x}{3}\)
x = \(\frac{1+4x}{12}\)
=> 12x = 1+4x
12x - 4x = 1
8x = 1
x = 1/8
a) \(x-\frac{5}{12}-\frac{4}{9}=\frac{-13}{18}\)
\(x-\frac{5}{12}=\frac{-13}{18}+\frac{4}{9}\)
\(x-\frac{5}{12}=\frac{-13}{18}+\frac{8}{18}\)
\(x-\frac{5}{12}=\frac{-5}{18}\)
\(x=\frac{-5}{18}+\frac{5}{12}\)
....
B=\(\left(6\frac{4}{9}+3\frac{7}{11}\right)-4\frac{4}{9}\)
C=\(\frac{-5}{7}x\frac{2}{11}+\frac{-5}{7}x\frac{9}{11}+1\frac{5}{7}\)
D=\(0,7x2\frac{2}{3}x20x0,375x\frac{5}{28}\)
E=(-6,17+\(3\frac{5}{9}-2\frac{36}{97}\))x\(\left(\frac{1}{3}-0,25-\frac{1}{2}\right)\)
giúp mình gấp nha ai lam dc câu nào thì làm
B=\(6\frac{4}{9}-4\frac{4}{9}+3\frac{7}{11}\)
B=\(2+3\frac{7}{11}\)
B=\(5\frac{7}{11}\)
B = \(5\frac{7}{11}=\frac{62}{11}\)
C = 1
D = \(\frac{5}{2}=2\frac{1}{2}\)