Tìm x :
a) x : 0.25 + x : 0.1 = 10.3
b) x * 3 : 7.5 + 42.6 = 51.6
c) 4/7 : x * 3/2 + 1/2 = 13/7
Bài 1:
a) Tìm x: 75%* x+3/4*x +x=30
b)tính giá trị bieu thức: 1/2:0.5-1/4:0.25+1/8:0.125-1/10:0.1
bài 1 : tìm x
a ) 2/3 . X = 2/7
b ) X : 8/13 = 13/7
c ) 3/2 : X = 7/4
a)\(x=\dfrac{2}{7}:\dfrac{2}{3}=\dfrac{3}{7}\)
b)\(x=\dfrac{13}{7}\times\dfrac{8}{13}=\dfrac{8}{7}\)
c)\(x=\dfrac{3}{2}:\dfrac{7}{4}=\dfrac{6}{7}\)
870 - x : 11 x 87 = 261 x : 0.25 x 2.3 = 6.9 2 x (y + y ) = 8.16 y x 1.5 + y + y x 7.5 = 59.8 m : 1/6 + m : 0.25 = 152 m : 1/3 + m : 0.25 = 1.4 giải dùm mình gấp nhé
870 - x : 11 x 87 = 261
x : 11 x 87 = 870 - 261
x : 11 x 87 = 609
x : 11 = 609 : 87
x : 11 = 7
x = 7 x 11
x = 77
x : 0.25 x 2.3 = 6.9
x : 0.25 = 6.9 : 2.3
x : 0.25 = 3
x = 3 x 0.25
x = 0.75
2 x (y + y) = 8.16
y + y = 8.16 : 2
y x 2 = 4.08
y = 4.08 : 2
y = 2.04
y x 1.5 + y + y x 7.5 = 59.8
y x (1.5 + 1 + 7.5) = 59.8
y x 10 = 59.8
y = 59.8 : 10
y = 5.98
m : 1/6 + m : 0.25 = 152
m : 1/6 + m : 1/4 = 152
m x 6 + m x 4 = 152
m x (6 + 4) = 152
m x 10 = 152
m = 152 : 10
m = 15.2
m : 1/3 + m : 0.25 = 1.4
m : 1/3 + m : 1/4 = 1.4
m x 3 + m x 4 = 1.4
m x (3 + 4) = 1.4
m x 7 = 1.4
m = 1.4 : 7
m = 0.2
7.5.(-2)= -54-18= bài 2 tìm x x+4=-12 bài 3 tìm số nguyên x biết : 3x-5=-7-13
1.
7.5.(-2)=12.(-2)=-24
-54-18=-72
2.
x+4=-12
x=-12-4
x=-16
Vậy x=-16
3.
3x-5=-7-13
3x-5=-20
3x=-20+5
3x=-15
x=-15:3
x=-5
Vậy x=-5
1/ (\(\left(-\dfrac{2}{3}\right)\)\(^2\) x \(\dfrac{-9}{8}\) - 25% x \(\dfrac{-16}{5}\)
2/ -1\(\dfrac{2}{5}\) x 75% + \(\dfrac{-7}{5}\) x 25%
3/ -2\(\dfrac{3}{7}\) x (-125%) + \(\dfrac{-17}{7}\) x 25%
4/ (-2)\(^3\) x (\(\dfrac{3}{4}\) x 0.25) : (2\(\dfrac{1}{4}\) - 1\(\dfrac{1}{6}\))
1) Ta có: \(\left(-\dfrac{2}{3}\right)^2\cdot\dfrac{-9}{8}-25\%\cdot\dfrac{-16}{5}\)
\(=\dfrac{4}{9}\cdot\dfrac{-9}{8}-\dfrac{1}{4}\cdot\dfrac{-16}{5}\)
\(=\dfrac{-1}{2}+\dfrac{4}{5}\)
\(=\dfrac{-5}{10}+\dfrac{8}{10}=\dfrac{3}{10}\)
2) Ta có: \(-1\dfrac{2}{5}\cdot75\%+\dfrac{-7}{5}\cdot25\%\)
\(=\dfrac{-7}{5}\cdot\dfrac{3}{4}+\dfrac{-7}{5}\cdot\dfrac{1}{4}\)
\(=\dfrac{-7}{5}\left(\dfrac{3}{4}+\dfrac{1}{4}\right)=-\dfrac{7}{5}\)
3) Ta có: \(-2\dfrac{3}{7}\cdot\left(-125\%\right)+\dfrac{-17}{7}\cdot25\%\)
\(=\dfrac{-17}{7}\cdot\dfrac{-5}{4}+\dfrac{-17}{7}\cdot\dfrac{1}{4}\)
\(=\dfrac{-17}{7}\cdot\left(\dfrac{-5}{4}+\dfrac{1}{4}\right)\)
\(=\dfrac{17}{7}\)
4) Ta có: \(\left(-2\right)^3\cdot\left(\dfrac{3}{4}\cdot0.25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=\left(-8\right)\cdot\left(\dfrac{3}{4}\cdot\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
\(=\left(-8\right)\cdot\dfrac{3}{16}:\dfrac{54-28}{24}\)
\(=\dfrac{-3}{2}\cdot\dfrac{24}{26}\)
\(=\dfrac{-72}{52}=\dfrac{-18}{13}\)
Tính
a. A= (2.872 x 0.25 + 2.166 : 0.1) x 0.05
b. B= (2-1/4+1/3-3/5)/(3-1/5-5/3) & viết kết quả dưới dạng hỗn số
bài1: thực hiện phép tính : đây là số nguyên tố
A= 5 2/7 . 8/11+5 2/7.5/11-5 2/7.2/11
B=(3 10/99+4 11/99-58/99).1/2-1/3-1/6)
bài 2 : tìm x biết ; mấy số như 5 4/7 là số nguyên tố nha các bạn
a, x:3 1/15=11/2 b,x.15/18=3/20
c, 5 4/7:x=13 d, ( 2 3/4-1 4/5).x=1
3/2 . x + 3/7 = -4/5
-11/12 . x + 0.25 =5/6
(x - 2)2 =1
(2x - 1)3 = -8
\(\dfrac{3}{2}x+\dfrac{3}{7}=-\dfrac{4}{5}\)
\(\Leftrightarrow\dfrac{3}{2}x=-\dfrac{43}{35}\)
\(\Leftrightarrow x=-\dfrac{86}{105}\)
Vậy \(x=-\dfrac{86}{105}\)
\(-\dfrac{11}{12}x+0,25=\dfrac{5}{6}\)
\(\Leftrightarrow-\dfrac{11}{12}x+\dfrac{1}{4}=\dfrac{5}{6}\)
\(\Leftrightarrow-\dfrac{11}{12}x=\dfrac{7}{12}\)
\(\Leftrightarrow x=-\dfrac{7}{11}\)
Vậy \(x=-\dfrac{7}{11}\)
\(\left(x-2\right)^2=1\)
\(\Leftrightarrow\left(x-2\right)^2-1=0\)
\(\Leftrightarrow\left(x-2-1\right)\left(x-2+1\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\x-1=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)
Vậy x = {3; 1}\(\left(2x-1\right)^3=-8\)
\(\Leftrightarrow2x-1=-2\)
\(\Leftrightarrow2x=-1\)
\(\Leftrightarrow x=-\dfrac{1}{2}\)
Vậy \(x=-\dfrac{1}{2}\)
(x - 2)2 = 1
<=>\(\left[{}\begin{matrix}x-2=1\\x-2=-1\end{matrix}\right.< =>\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)
Vậy x = 3; 1
(2x - 1)3 = -8
<=> 2x - 1 = -2
<=> 2x = -1
<=> x = \(\dfrac{-1}{2}\)
Vậy x = \(\dfrac{-1}{2}\)
\(|\) 2,5 - x\(|\) = 1,3
1,6- \(|\)x - 0,2 \(|\)= 0
13x = 169
\(\dfrac{-2}{x}\)=\(\dfrac{-x}{8\dfrac{ }{25}}\)
\(\dfrac{x}{-15}\)=\(\dfrac{-60}{x}\)
\(|\)x\(|\)+0,573=2
Tìm x biết: a) x + \(\dfrac{2}{3}=\dfrac{4}{27}\) b) \(\dfrac{3}{4}x-\dfrac{7}{3}=\dfrac{1}{4}x+\dfrac{1}{6}\)
c) \(\dfrac{13}{10}x-\dfrac{5}{2}=\dfrac{7}{2}\) d) (3\(x\) + 2) \(\left(\dfrac{-2}{5}x-7\right)=0\)
a: x=4/27-2/3=4/27-18/27=-14/27
b: =>3/4x-1/4x=1/6+7/3
=>1/2x=1/6+14/6=5/2
hay x=5
c: =>13/10x=7/2+5/2=6
=>x=13/10:6=13/60
d: (3x+2)(-2/5x-7)=0
=>3x+2=0 hoặc 2/5x+7=0
=>x=-2/3 hoặc x=-35/2
a: x=4/27-2/3=4/27-18/27=-14/27
b: =>3/4x-1/4x=1/6+7/3
=>1/2x=1/6+14/6=5/2
hay x=5
c: =>13/10x=7/2+5/2=6
=>x=13/10:6=13/60
d: (3x+2)(-2/5x-7)=0
=>3x+2=0 hoặc 2/5x+7=0
=>x=-2/3 hoặc x=-35/2