Bài 1 : <,>,=
a) 7/8 .... 8/7 b) 381/17 .... 381/71 c) 3/15 .... 2/5
a,-8/3+7/5+-71/15<x<-13/7+19/14+-7/2
b,-19/6+-15/2+11/3<x<-5/4+19/12+-10/3
c,-6/7+3/35<x<-2/5+3/7
d,x=3/4+1/-12
e,x/14=1/7+-3/14
f,11/18+13/6=85/x
g,8/17+5/17<x/17<6/17+9/17
a: =35/17-18/17-9/5+4/5
=1-1=0
b: =-7/19(3/17+8/11-1)
=7/19*18/187=126/3553
c: =26/15-11/15-17/3-6/13
=1-6/13-17/3
=7/13-17/3=-200/39
Bài 1 Tính nhanh
a) -3/7 + 5/13 + 3/7
b) -5/21+-2/21+8/24
c) -5/11+(-6/11+2)
d) (-1/32+1/2)+15/32
e)5/17+ -6/13 + 3/4 + 7/-13+12/17
f) 7/23+-18/18+-4/9+16/23+-5/8
g)1/3+-3/4+3/5+-1/36+1/15+-2/9
h)-1/2+1/3+-1/4+-2/8+4/18+4/9
a)\(-\dfrac{3}{7}+\dfrac{5}{13}+\dfrac{3}{7}\)
=\(\left(-\dfrac{3}{7}+\dfrac{3}{7}\right)+\dfrac{5}{13}\)
=\(0+\dfrac{5}{13}\)
=\(\dfrac{5}{13}\)
Tính nhanh
A =2/7 + - 3/8 + 11/7 + 1/3 + 1/5 + 5/-8
B = - 3/17 + ( 2/13 + 3/17 )
C = -3/8 + 12/15 + 5/-8
A = 2/7 + 11/7 -3/8 - 5/8 + 1/3 + 1/5 = 13/11 - 1 + 8/15
A = 2/11 + 8/15 = 118/125
B = - 3/17 + 3/17 + 2/13 = 2/13
C = - 3/8 - 5/8 + 12/15 = 1 - 12/15
C = - 1/5
Bài 1 :
a, 1/5 + 3/17 - 4/3 + ( 4/5 - 3/17 + 1/3 ) - 7/15 + [ - 14/30 ]
b, ( 5/8 - 4/13 + 3/2 ) - ( 5/8 + 9/13 ) - [ -3/2 ] + 7/-15
a) \(\frac{1}{5}+\frac{3}{17}-\frac{4}{3}+\left(\frac{4}{5}-\frac{3}{17}+\frac{1}{3}\right)-\frac{7}{15}+\left(\frac{-14}{30}\right)\)
\(=\left(\frac{1}{5}+\frac{4}{5}\right)+\left(\frac{3}{17}-\frac{3}{17}\right)-\left(\frac{4}{3}-\frac{1}{3}\right)-\left(\frac{7}{15}+\frac{14}{30}\right)\)
\(=1+0-1-\left(\frac{7}{15}+\frac{7}{15}\right)\)
= -14/15
b) \(\left(\frac{5}{8}-\frac{4}{13}+\frac{3}{2}\right)-\left(\frac{5}{8}+\frac{9}{13}\right)-\left(\frac{-3}{2}\right)+\frac{7}{-15}\)
\(=\frac{5}{8}-\frac{4}{13}+\frac{3}{2}-\frac{5}{8}-\frac{9}{13}+\frac{3}{2}-\frac{7}{15}\)
\(=\left(\frac{5}{8}-\frac{5}{8}\right)-\left(\frac{4}{13}+\frac{9}{13}\right)+\left(\frac{3}{2}+\frac{3}{2}\right)-\frac{7}{15}\)
\(=0-1+3-\frac{7}{15}\)
\(=2-\frac{7}{15}\)
\(=\frac{23}{15}\)
a) 1/5 +3/17-4/3+4/5-3/17+1/3-7/15-14/30
= (1/5+4/5)-4/3+1/3-(7/15+14/30)
=1-1-28/30=-28/30
Bài 12: Tính :
a) A = 1 + (-3) + 5 + ( - 7) +….+ 17 + ( -19);
b) B = (- 2) + 4 + (-6) + 8 + …+ ( - 18) + 20;
c) C = 1 + (-2) + 3 + (-4) + ….+ 1999 + ( - 2000) + 2001;
Bài 13: Tìm số nguyên x, biết:
a) –x + 20 = -(-15) –(+8) + 13
b) –(-10) + x = -13 + (-9) + (-6)
Bài 13:
a: =>20-x=15-8+13=20
hay x=0
Bài 1 : Rút gọn :
a)b)1/√5-2 +1−√5+2
b,3√2-2√8+1/2√32−√50
c)√7+√5√7−√5+√7−√5√7+√57+57−5+7−57+5
d) (√14−√71−√2+√15−√51−√3)1√7−√5
Anh em giúp mình nhớ mai mình kiểm tra rồi nhé
Bài 1: Tìm x:a) x - 2 + 7 = 1 . 3 . -9
b) 4 . x - 1 = (-5) 5 12 2 4 16 9 2 9
c) -2 . x + 5 = 7
d) 2 . x : 7 . 1 = 29 3 8 12 5 3 8 15
Bài 2: Tính:
a) 2 + 1 . 4
b) 0,8 : [ 4 . 1,25] - [ 0,64 - 1 ] 5 7 5 258 - 1 : 3 2 5
c) 8 : [ 7 - 12 ]
d) ( 1,08 - 2 ) : 4 + ( 59 - 13 ). 36 9 2 7 25 7 9 4 17
Bài 1: Tìm \(x\)
a; \(x-2\) + 7 = 1.3.(-9)
\(x\) - 2 + 7 = 3.(-9)
\(x\) - 2 + 7 = - 27
\(x\) = - 27 - 7 + 2
\(x\) = - 34 + 2
\(x\) = - 32
Vậy \(x=-32\)
Bài 1
c; - 2\(x\) + 5 = 7
- 2\(x\) = 7 - 5
- 2\(x\) = - 2
\(x\) = -2 : (-2)
\(x\) = - 1
Vậy \(x\) = - 1
Bài 1 b; d xem lại đề bài xem chỗ trống giữa các số là dấu gì!
Thực hiện phép tíh:( tíh nhah nếu có thể )
a, 3/17 : 4/13 - 1/13 x 1/5.
b,1/8 : (1/3 - 1/7) - (2/5 + 1/15) x 5/2.
c, 20/7 x 13/8 + 71/8 x 20/8 - 13/8 x 20/8.
Gỉai giúp mk nhak ! Tick cho 5 Pn trả lời cả cách lm lẫn đáp án . Oke ^^
/ là phần nhak, mk ko viết đc !
Mk làm theo cách lớp 5 nha
\(a,\frac{3}{17}:\frac{4}{13}-\frac{1}{13}\cdot\frac{1}{5}\)
\(=\frac{39}{68}-\frac{1}{65}\)
\(=\frac{2467}{4420}\)