a) X x 3/8 = 31/3 -4
b) X:5 = 8/7 + 2
Câu a7/8 chia đóng ngoặc 2/9 - 18 đóng ngoặc + 7/8 x 1/36 - 5/12 câu b 3/7 x 4/9 + 3/7 x 5/9 chia 6/12 câu c 5^8 x 16/31 - 5^8 x 47/31 + 1/3 câu d 7/2 x 3/8 + 7/2 x 5/8 chia 4/15
a: =7/8:(2/9-18+1/36)-5/12
=-7/142-5/12=-397/852
b: =3/7(4/9+5/9:6/12)=2/3
c: =5^8(16/31-47/31)+1/3=-5^8+1/3
d: =7/2(3/8+5/8:4/15)=609/64
Tính:
a) 6 - 2/5 + 3/5 x 3
b) ( 31/35 - 4/7 ) x 8/7 : 2
a) \(6-\dfrac{2}{5}+\dfrac{3}{5}\) x \(3\)
\(=6-\dfrac{2}{5}+\dfrac{9}{5}\)
\(=\dfrac{30}{5}-\dfrac{2}{5}+\dfrac{9}{5}\)
\(=\dfrac{30-2+9}{5}=\dfrac{37}{5}\)
b) \(\left(\dfrac{31}{35}-\dfrac{4}{7}\right)\) x \(\dfrac{8}{7}:2\)
\(=\left(\dfrac{31}{35}-\dfrac{20}{35}\right)\) x \(\dfrac{8}{7}:2\)
\(=\dfrac{11}{35}\) x \(\dfrac{8}{7}:2\)
\(=\dfrac{11}{35}\) x \(\dfrac{8}{7}\) x \(\dfrac{1}{2}\)
\(=\dfrac{\text{11 x 8 x 1}}{\text{ 35 x 7 x 2}}=\dfrac{88}{490}=\dfrac{88}{245}\)
a) 6−25+356−25+35 x 33
=6−25+95=6−25+95
=305−25+95=305−25+95
=30−2+95=375=30−2+95=375
b) (3135−47)(3135−47) x 87:287:2
=(3135−2035)=(3135−2035) x 87:287:2
=1135=1135 x 8
a) x + 5/7 = 3/7
b) 3/4-x=1/2
c) X x 3/8 = 31 /3
d) x:5=8/7
Tìm x
a,x=3/7-5/7=-2/7
x=3/4-2/4=1/4x=31/3.8/3=248/9x=8/7.5=40/7Viết dưới dạng các lũy thừa sau
a) \(a^3\),\(a^5\),\(x^7\),\(x^4\),\(3^5\),\(8^5\),\(2^3\).
b) \(31^5\),\(3^5\),\(4^6\),\(9^8\),\(3^2\)
giúp em nhanh với ạ
tìm x thuộc Z
a) 1/3 + (-2)/5 + 1/6 + (-1)/5 < x < ( -3)/4 + 2/7 + (-1)/4 + 3/5 + 5/7
b) 5/17 + (-4)/9 + (-20)/31 + 12/17 + (-11)/31 < x/9 < (-3)/7 + 7/15 + 4/(-7) + 8/15 +2/3
Tính :
a) 6 - 2 / 5 + 3 / 5 x 3
b) ( 31 / 35 - 4 / 7 ) x 8 / 7 ; 2
\(\frac{6-2}{5}+\frac{3}{5.3}\)
\(=\frac{4}{5}+\frac{1}{5.1}\)
\(=\frac{4}{5}+\frac{1}{5}\)
\(=\frac{5}{5}=1\)
a. 6 x 3 - ( \(\frac{2}{5}+\frac{3}{5}\)) = 6 x 3 - \(\frac{5}{5}\)= 6 x 3 - 1 = 18 - 1 = 17
b.( \(\frac{31}{35}-\frac{4}{7}\)) x \(\frac{8}{7}\): 2 =\(\frac{11}{35}\)x \(\frac{8}{7}\): 2 =\(\frac{88}{245}\): 2 = \(\frac{88}{490}\)= \(\frac{44}{245}\)= ...........rút gọn đến khi hết
Tính :
a) 6 - 2 / 5 + 3 / 5 x 3
b) ( 31 / 35 - 4 / 7 ) x 8 / 7 ; 2
a) \(6-\frac{2}{5}+\frac{3}{5}\times3\)
\(=6-\frac{2}{5}+\frac{9}{5}\)
\(=\frac{30}{5}-\frac{2}{5}+\frac{9}{5}\)
\(=\frac{28}{5}+\frac{9}{5}\)
\(=\frac{37}{5}\)
b) \(\left(\frac{31}{35}-\frac{4}{7}\right)\times\frac{8}{7}:2\)
\(=\frac{11}{35}\times\frac{8}{7}:2\)
\(=\frac{88}{245}:2\)
\(=\frac{44}{245}\)
bài 2 viết mỗi tích, thương sau dưới dạng luỹ thừa
a) 4^10 x 2^30 b) 9^25 x 27^4 x 81^3 c) 25^50 x 125^5 d) 64^3 x 4^8 x 16^4
e)3^8:3^6 ; 2^10:8^3 ; 12^7 :6^7 ; 31^5 ; 81^3
f) 5^8 : 25^2 ; 4^9:64^2 ; 2^25 : 32^4 ; 125^3 : 25^4
a, 410. 230=220.230=250
b,925.274.813= 350.312.312=374
Tương tự các câu khác....
a, 410.230 = (22)10.230 = 220.230 = 250
b, 925.274.813 = (32)25.(33)4.(34)3 = 350.312.312 = 374
c, 2550.1255 = (52)50.(53)5 = 5100.515 = 5115
d, 643.48.164 = (26)3.(22)8.(24)4 = 218.216.216 = 250
e, 38 : 36 = 32
210 : 83 = 210 : (23)3 = 210 : 29 = 2
127 : 67 = (12 : 6)7 = 27
@Dương Tuyết Mai
Bài 3. Tìm x biết
a, (10/3: x).(-5/4)=-5/3-5/3
b, (-6/5+ x):(-18/5)=-7/4+1/4:1/8
c, -22/15. x +1/3=-3/5+1/5
d,(0,25-30% x).1/3-1/4=-31/6
e, (0,5 x-3/7):1/2=8/7
Thank you very much !
a, (10/3:x).(-5/4)=-10/3
10/3:x=-10/3:(-5/4)
10/3:x=8/3
x=10/3:8/3
x=5/4
b,(-6/5+x):(-18/5)=-1/4
-6/5+x=-1/4.(-18/5)
-6/5+x=9/10
x=9/10-(-6/5)=9/10+6/5
x=21/10
c,-22/15.x+1/3=-2/5
-22/15.x=-2/5-1/3=-11/15
x=-11/15:(-22/15)
x=11/21
d,(0,25-30%x).1/3=-31/6+1/4=-59/12
1/4-3/10x=-59/12:1/3=-59/4
3/10x=1/4-(-59/4)=1/4+59/4=15
x=15:3/10
x=50
e,(0,5x-3/7):1/2=8/7
1/2x=8/7.1/2=4/7
x=4/7:1/2
x=8/7