tìm x
(X-12,5) : 3/4 = 8/5
(X-2/5) x5/11=75/22
22 /5 x 6 / 121 x 11/4 x3/5 x 1/3 x5 /4
\(\dfrac{22}{5}\times\dfrac{6}{121}\times\dfrac{11}{4}\times\dfrac{3}{5}\times\dfrac{1}{3}\times\dfrac{5}{4}\)
\(=\left(\dfrac{22}{5}\times\dfrac{5}{4}\right)\times\left(\dfrac{6}{121}\times\dfrac{11}{4}\right)\times\left(\dfrac{3}{5}\times\dfrac{1}{3}\right)\)
\(=\dfrac{11}{2}\times\dfrac{3}{22}\times\dfrac{1}{5}\)
\(=\dfrac{3}{20}\)
\(=\dfrac{22\times6\times11\times3\times1\times5}{5\times121\times4\times5\times3\times4}=\dfrac{11\times2\times6\times11\times1}{11\times11\times4\times5\times4}=\dfrac{2\times6\times1}{4\times5\times4}=\dfrac{18}{100}=\dfrac{9}{50}\)
Tìm x : bt
a , 22/7 : ( 11 - x ) + 2/3 = 7/5
b , 22 * ( x + 1 ) - 12,5 = 53,5
c , ( x - 1/2 ) * 5/2 +1/2 = 7/4
d , x + x * 1/4 : 2/7 + x : 2/9 = 255
a) \(\frac{22}{7}:\left(11-x\right)+\frac{2}{3}=\frac{7}{5}\)
\(\frac{22}{7}:\left(11-x\right)=\frac{7}{5}-\frac{2}{3}\)
\(\frac{22}{7}:\left(11-x\right)=\frac{11}{15}\)
\(11-x=\frac{22}{7}:\frac{11}{15}\)
\(11-x=\frac{30}{7}\)
\(x=11-\frac{30}{7}\)
\(x=\frac{47}{7}\)
b) \(22.\left(x+1\right)-12,5=53,5\)
\(22.\left(x+1\right)=53,5+12,5\)
\(22.\left(x+1\right)=66\)
\(x+1=66:22\)
\(x+1=3\)
\(x=3-1\)
\(x=2\)
c) \(\left(x-\frac{1}{2}\right).\frac{5}{2}+\frac{1}{2}=\frac{7}{4}\)
\(\left(x-\frac{1}{2}\right).\frac{5}{2}=\frac{7}{4}-\frac{1}{2}\)
\(\left(x-\frac{1}{2}\right).\frac{5}{2}=\frac{5}{4}\)
\(x-\frac{1}{2}=\frac{5}{4}:\frac{5}{2}\)
\(x-\frac{1}{2}=\frac{1}{2}\)
\(x=\frac{1}{2}+\frac{1}{2}\)
\(x=1\)
a)22/7:(11-x)=7/5-2/3
22/7:(11-x)=11/15
11-x=22/7:11/15
11-x=30/7
x=11-30/7
x=47/7
vậy x=47/7
b)22.(x+1)=53,5+12,5
22.(x+1)=66
x+1=66:2
x+1=3
x=3-1
x=2
vậy x=2
c)(x-1/2).5/2=7/4-1/2
(x-1/2).5/2=5/4
x-1/2=5/4:5/2
x-1/2=1/2
x=1/2+1/2
x=1
vậy x=1
bạn hãy tích đúng cho mình nhé
1.a,(x-12,5):3/4=8/5
b,(x-2/5)x5/11=75/22
2.DT mot tam bang HCN la3,575m2,CR cua tam bang la 130cm.Ng ta muon nep xung quanh tam bang do bang khung nhom.Hoi khung nhom do dai bn m?
3.Cuoi nam 2003 so dan mot huyen la 93750ng.Neu muc tang dan so hang nam la 1,6% thi den cuoi nam 2005 so dan huyen do la bn ng?
Giai giup vs a~Iu lem a~Mong cac ben iu lam giup bit bai neo lam bai do ko bat buoc nhoa,nhanh mk tick choa 3 tick lun nhe!I LOVE YOU PAC PAC!:3333
1.
a. (x - 12,5) : 3/4 = 8/5
x - 12,5 = 8/5 x 3/4
x = 6/5 + 12,5
x = 137/10 = 13.7
1.
b, (x -2/5) x 5/11 = 75/22
x - 2/5 = 75/22 : 5/11
x = 15/2 + 2/5
x = 79/10 = 7.9
Mon ben ak,con 2bai bai nx thui a~ ban neo giup mk nx thi 1 hom mk k cho 3 k trong 1 thang ngay nao mk cx k choa lun!
Bài 1:Tính hợp lí
a)-12,5+17,55-3,5+2,45
b)0,175-(\(2\dfrac{1}{3}\)+0,175)
c)\(\dfrac{5}{13}\).\(\dfrac{-3}{10}\)+\(\dfrac{3}{10}\).\(\dfrac{-8}{13}\)+(-0,7)
Bài 2:Tìm x biết
a)x+\(\dfrac{2}{5}\)=2,4
b)2x-\(\dfrac{4}{5}\)=-1,5
c)11-(15+11)=x-(25-9)
Bài 3:Cho A=\(\dfrac{1}{2^2}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{4^2}\)+\(\dfrac{1}{5^2}\)+....+\(\dfrac{1}{100^2}\)
Chứng tỏ A<1
2:
a: x=2,4-0,4=2
b: =>2x=-1,5+0,8=-0,7
=>x=-0,35
c: =>x-16=-15
=>x=1
Thực hiện phép tính:
A) 7/38 x 9/11 +7/38 x 4/11 -7/38 x 2/11
B) 5/31 x 21/25 + 5/31 x -7/10 - 5/31 x 9/20
C) ( -2/3 + 3/7 ) : 4/5 + (-1/3 + 4/7 ) : 4/5
D) 5/9 : ( 1/11 -5/22 ) + 5/9 : ( 1/15 - 2/3 )
E) 3/14 : 1/28 -13/21 : 1/28 + 29/42 : 1/28 - 8
F) ( -40/51 x 0,32 x17/20) : 64/75
Đây là dấu x ( là nhân ) mọi người nhé
mong mn giúp em ạ
A) 7/38 x 9/11 +7/38 x 4/11 -7/38 x 2/11
=7/38.(9/11+4/11-2/11)
=7/38
B) 5/31 x 21/25 + 5/31 x -7/10 - 5/31 x 9/20
=5/31.(21/25-7/10-9/20)
=5/31.(-31/100)
=-1/20
tính nhanh
B = 3/2 x5 + 3/5 x 8 + 3/8 x 11 + 3/11 x 14
Bài 1: Thực hiện phép tính:
1, 4/23 + 5/21 + 0,5 - 4/23 + 16/21
2, (1/3 + 12/67 + 13/41)-(79/67 - 28/41)
3, 12,5 x (-5/7)+1,5 x (-5/7)
4, 3/8x19 1/3- 3/8x33 1/3
5, 5/7x(-3/11)+5/7x(-8/11)+2 5/7
6, (-5/11:13/8-5/11:13/5)- giá trị tuyệt đối của -1/33
1: \(\dfrac{4}{23}+\dfrac{5}{21}+\dfrac{1}{2}-\dfrac{4}{23}+\dfrac{16}{21}\)
\(=1+\dfrac{1}{2}\)
\(=\dfrac{3}{2}\)
2: \(\left(\dfrac{1}{3}+\dfrac{12}{67}+\dfrac{13}{41}\right)-\left(\dfrac{79}{67}-\dfrac{28}{41}\right)\)
\(=\dfrac{1}{3}+\dfrac{12}{67}+\dfrac{13}{41}-\dfrac{79}{67}+\dfrac{28}{41}\)
\(=\dfrac{1}{3}\)
37 x 5^4 trên 25 ^ 2
2 ^4 x 2^6 x 3^8 x 9^2 trên 4^4 x 3^11
3 x 9^4 x 9^3 trên 3^2 x 9
125 x 5 x 64 - 25^3 x10 x 4 trên 5^7 x 8
\(\dfrac{37\cdot5^4}{25^2}=\dfrac{37\cdot5^4}{5^4}=37\\ \dfrac{2^4\cdot2^6\cdot3^8\cdot9^2}{4^4\cdot3^{11}}=\dfrac{2^{10}\cdot3^8\cdot3^4}{2^8\cdot3^{11}}=2^2\cdot3=12\\ \dfrac{3\cdot9^4\cdot9^3}{3^2\cdot9}=\dfrac{3\cdot3^8\cdot3^6}{3^2\cdot3^2}=3^{11}\\ \dfrac{125\cdot5\cdot64-25^3\cdot10\cdot4}{5^7\cdot8}=\dfrac{5^3\cdot5\cdot2^6-5^6\cdot2\cdot5\cdot2^2}{5^7\cdot2^3}=\dfrac{5^4\cdot2^3\left(2^3-5^3\right)}{5^7\cdot2^3}=\dfrac{8-125}{5^3}=\dfrac{-117}{125}\)
Tìm x:
a, (x+2)+(x+5)+(x+8)+(x+11)+(x+14)=75
b,(x+1)+(x+3)+(x+5)+...+(x+101)=5400
c,(x+1)+(x+4)+(x+7)+...+(x+94)=1840
a, (x+2)+(x+5)+(x+8)+(x+11)+(x+14)=75
5x + (2 + 5 + 8 + 11 + 14) = 75
5x + 40 = 75
5x = 35
x = 7
Các câu dưới tương tự.
a)(x+2)+(x+5)+(x+8)+(x+11)+(x+14)=75
x+x+x+x+x+2+5+8+11+14=75
5xx+40=75
5xx=75-40
5xx=35
x=35:5
x=7
b)(x+1)+(x+3)+(x+5)+....+(x+101)=5400
Nhận thấy dãy trên có (101-1):2+1=51(số) nên có 51 x
Tách như câu a
51xx+(1+3+5+...+101)=5400
51xx+[(101+1)x51:2]=5400
51xx+2601=5400
51xx=5400-2601
51xx=2799
x=2799:51
x=933/17
c)(x+1)+(x+4)+(x+7)+....+(x+94)=1840
Phần c này cũng giống phần b,em dựa vào mà làm nhé,giống,khác mỗi số thôi
Chúc em họ tốt^^