Tìm x biết:
a) |x=3|=15
b) |x-7|+13=25
c) |x-3|-16=-4
d) 26-|x+9|=-13
tìm số nguyên x,y biết:
a)-2/3=y/15
b)2/x=x/18
c)x/9=16/x
a: =>y/15=-2/3
hay y=-10
b: 2/x=x/18
nên \(x^2=36\)
hay \(x\in\left\{6;-6\right\}\)
c: x/9=16/x
nên \(x^2=144\)
hay \(x\in\left\{12;-12\right\}\)
Tìm x, biết:
a) | x+3 | = 15
b) | x-7 | + 13 = 13
c) | x-3 | - 16 = -4
d) 26 - | x+9 | = -13
a)
x-3=15
x = 15+3=18
b)
x+7-13=13
x+7 =13-13=0
x = 0-7=-7
c)
x+3-16=-4
x+3 =-4+16=12
x = 12-3=9
d)
26-x-9=-13
-x-9= -13-26=-39
-x =-39+9=-30
x=30
\(\left|x+3\right|=15\)
\(\Rightarrow\orbr{\begin{cases}x+3=15\\x+3=-15\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=12\\x=-18\end{cases}}\)
vậy_
\(\left|x-7\right|+13=13\)
\(\Rightarrow\left|x-7\right|=0\)
\(\Rightarrow x-7=0\)
\(\Rightarrow x=7\)
vậy_
tt
Bài 1: Lập các cặp phân số bằng nhau từ đẳng thức
a) 2 . 36 = 8 . 9
b) ( - 2 ) . ( - 18 ) = 4 . 9
Bài 2: Tìm x, y, z thuộc Z biết:
a) x/3 = - 12/ 9
b) - 4/8 = x/-10 = -7/9 = z/-24
c) - 26/13 ≤ x ≤ - 21/7
Giúp em với ạa
Bài 2 : a, x = -36/9 = -4
b, đề sai
c, <=> -2 =< x =< -3 => x = -1
Bài 1:
a: 2/8=9/36; 2/9=8/36; 8/2=36/9; 9/2=36/8
b: -2/4=9/-18; -2/9=4/-18; 4/-2=-18/9; 9/-2=-18/4
Bài 2:
a: =>x/3=-4/3
hay x=-4
Câu b đề sai rồi bạn
Tìm X biết
a/ |x+3|=15 b/|x-7|+13=25 c/|x-3|-16=-4 d/26-|x+9|=-13
tìm x , biết:
a) \(x\) : \(4\dfrac{1}{3}\) = -2,5 b) \(\dfrac{3}{5}x\) + \(\dfrac{1}{4}\) = \(\dfrac{1}{10}\)
c) \(2\dfrac{7}{9}\) \(-\) \(\dfrac{12}{13}x\) = \(\dfrac{7}{9}\) d)\(\dfrac{-2}{3}-\dfrac{1}{3}\)\(\left(2x-5\right)=\dfrac{3}{2}\)
a, \(x\) : \(\dfrac{13}{3}\) = -2,5
\(x\) = -2,5 . \(\dfrac{13}{3}\)
\(x\) = \(\dfrac{65}{6}\)
b,\(\dfrac{3}{5}\)\(x\) = \(\dfrac{1}{10}-\)\(\dfrac{1}{4}\)
\(\dfrac{3}{5}x\) = \(\dfrac{-3}{20}\)
\(x\) = \(\dfrac{-3}{20}\) : \(\dfrac{3}{5}\)
\(x\) = \(\dfrac{-1}{4}\)
c, \(\dfrac{25}{9}-\dfrac{12}{13}x=\dfrac{7}{9}\)
\(\dfrac{12}{13}x\)\(=\dfrac{25}{9}-\dfrac{7}{9}\)
\(\dfrac{12}{13}x=2\)
\(x=2:\dfrac{12}{13}\)
\(x=\dfrac{13}{6}\)
a) -5/8 + x = -7/6
b) x - -3/4 = -14/25
c) x. 9/-13 = -33/26
d) 4/-9 : x = -5/3
e) 4/7 .x - 2/3 = 1/5
f) 4/5 + 5/7 : x = 1/6
a: =>x=-7/6+5/8=-13/24
b: =>x=-14/25-3/4=-131/100
c: \(x=\dfrac{-33}{26}:\dfrac{-9}{13}=\dfrac{33}{26}\cdot\dfrac{13}{9}=\dfrac{11}{3}\cdot\dfrac{1}{2}=\dfrac{11}{6}\)
d: \(x=\dfrac{4}{9}:\dfrac{5}{3}=\dfrac{4}{9}\cdot\dfrac{3}{5}=\dfrac{12}{45}=\dfrac{4}{15}\)
tìm x , biết
a, /x + 3 / = 15 b, /x - 7 / + 13 = 25 c, /x -3 / - 16 = -4 d, 26 - / x +9 / = -13
a) \(\left|x+3\right|=15\)
\(\Rightarrow\orbr{\begin{cases}x=15-3\\x=-15-3\end{cases}\Rightarrow}\orbr{\begin{cases}x=12\\x=-18\end{cases}}\)
b) Đề sai
c) Đề sai
d) \(26-\left|x+9\right|=-13\)
\(\Rightarrow\left|x+9\right|=26-\left(-13\right)\)
\(\Rightarrow\left|x+9\right|=39\)
\(\Rightarrow\orbr{\begin{cases}x=39-9\\x=-39-9\end{cases}\Rightarrow\orbr{\begin{cases}x=30\\x=-48\end{cases}}}\)
Em ơi ở câu b,c ko có x thì sao mà làm
c,
,\(/x-3/-16=-4\\ =>/x-3/=12\\ =>\hept{\begin{cases}x-3=12\\x-3=-12\end{cases}}=>\hept{\begin{cases}x=15\\x=-9\end{cases}}\)
b,
\(/x-7/+13=25\\ =>/x-7/=12\\ =>\hept{\begin{cases}x-7=12\\x-7=-12\end{cases}}=>\hept{\begin{cases}x=19\\x=-5\end{cases}}\)
Ko pk sai đề đâu ~.~
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Bài 7:Tìm số nguyên x biết: a) 6:(x + 2) b) (x +13):(x +8) c) (3x + 2):(x −3) d) 3x+9:2x+1. |
b: \(\Leftrightarrow x+8\in\left\{1;-1;5;-5\right\}\)
hay \(x\in\left\{-7;-9;-3;-13\right\}\)
a ) 2/5 + 11/15
b ) 7/8 -7/9
c ) 11/13 x 26/31
d ) 1/2 : 1/3 x 2/5
mình chọn 4 người trò truyện
a) \(\dfrac{2}{5}+\dfrac{11}{15}=\dfrac{6}{15}+\dfrac{11}{15}=\dfrac{17}{15}\)
b) \(\dfrac{7}{8}-\dfrac{7}{9}=\dfrac{63}{72}-\dfrac{56}{72}=\dfrac{7}{72}\)
c) \(\dfrac{11}{13}\cdot\dfrac{26}{31}=\dfrac{26}{13}\cdot\dfrac{11}{31}=\dfrac{22}{31}\)
d) \(\dfrac{1}{2}:\dfrac{1}{3}\cdot\dfrac{2}{5}=\dfrac{1}{2}\cdot3\cdot\dfrac{2}{5}=\dfrac{3}{5}\)
a ) 2/5 + 11/15 = 6/15 + 11/ 15 = 17/15.
b ) 7/8 -7/9 = 63/72 -56/72 = 7/72.
c ) 11/13 x 26/31 = 22/31
d ) 1/2 : 1/3 x 2/5= 1/2 x 3/1 x 2/5 = 3/5
đúng thì tick mình nhé!!! cảm ơn bạn