tìm y
y x 4 7/12=6 1/4
y : 3 7/8=5 1/2
6 1/7 : y =5 2/5
1.Tìm y
a, y x 4 7/12 = 6 1/4
b, y : 3 7/8 = 5 1/2
c, 6 1/7 : y = 5 2/5
Tính:
a) -5/7(14/5 - 7/10) : |-2/3| - 3/4(8/9 + 16/3) + 10/3(1/3 + 1/5)
b) 17/-26(1/6 - 5/3) : 17/13 - 20/3(2/5 - 1/4) + 2/3(6/5 - 9/2)
c) -8/9(9/8 - 3/2) + 5/4 : (5/2 - 15/4) - 3/4(10/9 - 8/3) : (-1/3)
d) 21/10 : (12/5 - 9/10) . (-4/7) - 3/2(1/6 - 7/12) + 1/5(3/2 - 1/4)
a) Ta có: \(\dfrac{-5}{7}\left(\dfrac{14}{5}-\dfrac{7}{10}\right):\left|-\dfrac{2}{3}\right|-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)+\dfrac{10}{3}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\)
\(=\dfrac{-5}{7}\cdot\dfrac{3}{2}\cdot\dfrac{21}{10}-\dfrac{3}{4}\cdot\dfrac{56}{3}+\dfrac{10}{3}\cdot\dfrac{8}{15}\)
\(=\dfrac{-9}{4}-14+\dfrac{16}{9}\)
\(=\dfrac{-1621}{126}\)
b) Ta có: \(\dfrac{17}{-26}\cdot\left(\dfrac{1}{6}-\dfrac{5}{3}\right):\dfrac{17}{13}-\dfrac{20}{3}\left(\dfrac{2}{5}-\dfrac{1}{4}\right)+\dfrac{2}{3}\left(\dfrac{6}{5}-\dfrac{9}{2}\right)\)
\(=\dfrac{-17}{26}\cdot\dfrac{13}{17}\cdot\dfrac{-3}{2}-\dfrac{20}{3}\cdot\dfrac{3}{20}+\dfrac{2}{3}\cdot\dfrac{-33}{10}\)
\(=\dfrac{3}{4}-1-\dfrac{11}{5}\)
\(=-\dfrac{49}{20}\)
Bài 1 Tìm x,biết
x.3/5=2/3
x.7/17=17/8
3/4 chia x=-7/12
3/8 - 1/6.x=1/4
1/3+1/2 chia x=-4
Bài 2 Tính
-6/11 chia [3/5 . 4/11]
7/12 + 5/12 chia 6 -11/36
[4/5 + 1/2] chia [3/13 - 8/13]
[2/3 - 1/4 + 5/11] chia [5/12 + 1 -7/11]
*Dấu . là dấu nhân nha mn*
Bài 1:
a: \(x=\dfrac{2}{3}:\dfrac{3}{5}=\dfrac{2}{3}\cdot\dfrac{5}{3}=\dfrac{10}{9}\)
b: \(x=\dfrac{17}{8}:\dfrac{7}{17}=\dfrac{17}{8}\cdot\dfrac{17}{7}=\dfrac{289}{56}\)
c: \(x=-\dfrac{3}{4}:\dfrac{7}{12}=\dfrac{-3}{4}\cdot\dfrac{12}{7}=\dfrac{-63}{28}=-\dfrac{9}{4}\)
d: \(\Leftrightarrow x\cdot\dfrac{1}{6}=\dfrac{3}{8}-\dfrac{1}{4}=\dfrac{1}{4}\)
hay \(x=\dfrac{1}{4}:\dfrac{1}{6}=\dfrac{3}{2}\)
e: \(\Leftrightarrow\dfrac{1}{2}:x=-4-\dfrac{1}{3}=-\dfrac{17}{3}\)
hay \(x=-\dfrac{1}{2}:\dfrac{17}{3}=\dfrac{-3}{34}\)
1.Tìm x,y thuộc Z biết
1,x+(-45)=(-62)+17
2,x+29=|-43|+(-43)
3,43+(9-21)=317-(x+317)
4,|x|+|-4|=7
5,|x|+|y|=0
6,(15-x)+(x-12)=7-(-5+x)
7,(2x-5)^2=9
8,(2x+6).(x-9)=0
9,(1-3x)^3=-8
10,3x+4y-xy=15
3.Tìm x+y biết
|x|=5
|x|=7
4.Tìm giá trị lớn nhất hoặc nhỏ nhất của các biểu thức sau (x,y thuộc Z)
A=|x-3|+1
B=3-|x+1|
C=|x-5|+|y+3|+7
1.Tìm x,y thuộc Z biết
1,x+(-45)=(-62)+17
2,x+29=|-43|+(-43)
3,43+(9-21)=317-(x+317)
4,|x|+|-4|=7
5,|x|+|y|=0
6,(15-x)+(x-12)=7-(-5+x)
7,(2x-5)^2=9
8,(2x+6).(x-9)=0
9,(1-3x)^3=-8
10,3x+4y-xy=15
3.Tìm x+y biết
|x|=5
|x|=7
4.Tìm giá trị lớn nhất hoặc nhỏ nhất của các biểu thức sau (x,y thuộc Z)
A=|x-3|+1
B=3-|x+1|
C=|x-5|+|y+3|+7
1) Tính:
A= 1-2-3-4+5-6-7-8+9-10-11-12+...+97-98-99-100.
B= 1+2-3-4+5+6-7-8+9+10-11-12+...+197+198-199-200.
2) Tìm n € Z
a) n+2 chia hết n-1
b) n-7 chia hết 2n+3
c) n2-2 chia hết n + 3
d) n+5 chia hết 2n +1
3) Tìm x,y € N
a) 2xy + x - 4y = 10
b) 32y - 4xy - x= 12
c) ( x-2).(5y+1)=12
5/2x3/7-3/4:7/3=
5/4:15/12-5/4:1/2=
1/26+7/30+12/26+8/3
\(\dfrac{5}{2}\times\dfrac{3}{7}-\dfrac{3}{4}\div\dfrac{7}{3}=\dfrac{5}{2}\times\dfrac{3}{7}-\dfrac{3}{4}\times\dfrac{3}{7}=\dfrac{5}{2}\times\dfrac{3}{7}-\dfrac{3}{7}\times\dfrac{3}{4}\)
\(=\dfrac{3}{7}\times\left(\dfrac{5}{2}-\dfrac{3}{4}\right)=\dfrac{3}{7}\times\dfrac{7}{4}=\dfrac{3}{4}\)
\(\dfrac{5}{4}\div\dfrac{15}{12}-\dfrac{5}{4}\div\dfrac{1}{2}=\dfrac{5}{4}\times\dfrac{12}{15}-\dfrac{5}{4}\times2\)
\(=\dfrac{5}{4}\times\left(\dfrac{12}{15}-2\right)\)
\(=\dfrac{5}{4}\times\dfrac{-6}{5}=\dfrac{-3}{2}\)
\(\dfrac{1}{26}+\dfrac{7}{30}+\dfrac{12}{26}+\dfrac{8}{3}=\left(\dfrac{1}{26}+\dfrac{12}{26}\right)+\left(\dfrac{7}{30}+\dfrac{8}{3}\right)\)
\(=\dfrac{1}{2}+\dfrac{29}{10}=\dfrac{17}{5}\)
a, 2/3 x - 1/2 x = 5/12
b, ( x . 6 và 2/7 + 3/7 ) . 2 và 1/5 - 3/7 = - 2
c, x . 3 và 1/4 + ( - 7/6 ) . x - 1 và 2/3 = 5/12
d, 5 và 8/17 : x + ( - 4/ 17 ) : x + 3 và 1/7 : 17 và 1/3 = 4/11
e, ( x + 1/5 )2 + 17/25 = 26/25
g, - 1 và 5/27 - ( 3x - 7/9 )3 = - 24 /27
1.Tìm các số nguyên x:
5/17+-4/9+-20/31+12/17+-11/31<x<=-3/7+7/15+4/-7+8/15+2/3
2. Tính
A=5-10/19+15/143-5/81+8-16/26+24/243-8/181
6-12/19+18/143-6/81+9-18/26+27/243-9/181
Thực hiện phép tính:
1,-4/7 + 2/3x -9/14
2,17/13 - ( 4/13 - 11 )
3, 8 2/7 - ( 3 4/9 + 4 2/7 )
5, ( 2/3 - 1 1/2): 4/3 + 1/2
6, -5/13 + 2/5 + -8/13 + 3/5 - 3/7
7, 6/5 x 3/7 + 6/5 : 7/10 + 6/5
\(1,-\dfrac{4}{7}+\dfrac{2}{3}\times\dfrac{-9}{14}\)
\(=\dfrac{-4}{7}+\dfrac{-18}{42}\)
\(=\dfrac{-4\times6}{7\times6}+\dfrac{-18}{42}\)
\(=\dfrac{-20}{42}+\dfrac{-18}{42}\)
\(=-\dfrac{38}{42}\)
\(=-\dfrac{19}{21}\)
\(2,\dfrac{17}{13}-\left(\dfrac{4}{13}-11\right)\)
\(=\dfrac{17}{13}-\dfrac{4}{13}+11\)
\(=\dfrac{13}{13}+11\)
\(=1+11\)
\(=12\)
\(3,8\dfrac{2}{7}-\left(3\dfrac{4}{9}+4\dfrac{2}{7}\right)\)
\(=\dfrac{58}{7}-\left(\dfrac{31}{9}+\dfrac{30}{7}\right)\)
\(=\dfrac{58}{7}-\dfrac{31}{9}-\dfrac{30}{7}\)
\(=\dfrac{58}{7}-\dfrac{30}{7}-\dfrac{31}{9}\)
\(=\dfrac{28}{7}-\dfrac{31}{9}\)
\(=\dfrac{28\times9}{7\times9}-\dfrac{31\times7}{9\times7}\)
\(=\dfrac{252}{63}-\dfrac{217}{63}\)
\(=\dfrac{35}{63}\)
\(=\dfrac{5}{9}\)
\(5,\left(\dfrac{2}{3}-1\dfrac{1}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{2}{3}-\dfrac{3}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{2\times2}{3\times2}-\dfrac{3\times3}{2\times3}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{4}{6}-\dfrac{9}{6}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\dfrac{-5}{6}:\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\dfrac{-5}{6}\times\dfrac{3}{4}+\dfrac{1}{2}\)
\(=\dfrac{-15}{24}+\dfrac{1}{2}\)
\(=\dfrac{-15}{24}+\dfrac{1\times12}{2\times12}\)
\(=\dfrac{-15}{24}+\dfrac{12}{24}\)
\(=\dfrac{-3}{24}\)
\(=-\dfrac{1}{8}\)
\(6,\dfrac{-5}{13}+\dfrac{2}{5}+\dfrac{-8}{13}+\dfrac{3}{5}-\dfrac{3}{7}\)
\(=\left(\dfrac{-5}{13}+\dfrac{-8}{13}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{3}{7}\)
\(=\dfrac{-13}{13}+\dfrac{5}{5}-\dfrac{3}{7}\)
\(=-1+1-\dfrac{3}{7}\)
\(=-\dfrac{3}{7}\)
\(7,\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}:\dfrac{7}{10}+\dfrac{6}{5}\)
\(=\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}\times\dfrac{10}{7}+\dfrac{6}{5}\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+1\right)\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{1\times7}{1\times7}\right)\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{7}{7}\right)\)
\(=\dfrac{6}{5}\times\dfrac{20}{7}\)
\(=\dfrac{120}{35}\)
\(=\dfrac{24}{7}\)