a/ 1/2 + 5/6 + 11/12 + 19/20
b/ 1/2 + 5/6 + 11/12 + 19/20 + 29/30 + 41/42
c/ (1-1/3) + (1-1/15) + (1-1/35) + (1-1/63)
d/ 1/2 + 5/6 + 11/12 + ... + 9899/9900
e/ 2/3 + 14/15 + 34/35 +62/63
f/ 2/3 + 14/15 + 34/35 + ... + 9998/9999
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
bài 2: tính nhanh :
a) 3/8 + 7/12 + 10/16 + 10/24 b) 4/6 + 7/13 + 17/9 + 19/13 + 1/9 + 14/6
c) 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56
18x - 19 = 21+8x
g)18- 4x = -20-6x
h)-15x - 24 = - 7x +32
i) 15x- 3(4x - 6) = - 12+ 36
k) -10 x - 27 = - 7x +33
m) -17 x - 24 = - 9x - 40
n) -23x + 25 = - 18x +75
p) - 5x+ 7( 2x-3) = 4( x - 4)
q)24- 6(3x + 1) = -5( 4x- 4 ) - 8
r) 18-4. (6-2x) = -3.(4x +5 ) - 11
s) - 5. ( 4x-5) - 14 = 6.(2 - 3x) - 10x-9
giúp mik với giải cả cách làm nhé
1+2+3+4+5+6+7+8+9+10=
11+12+13+14+15+16+17+18+19+20=
1+2+3+4+5+6+7+8+9+10+11+12+13+14 +15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30-50-53=
bạn5 bạn nào làm nhanh mình sẽ tích cho bạn đó
[7x-19]-[5x-12]=3x-[9-2x]-1
1) 2) 3) 4) 5) 6) 7) 8 ) 9) / 10) 4 11) 12)
13) 14) 15)
16) 17)
18) 19)
n)8 . 9 . 14 + 6 . 17 . 12 + 19 . 4 . 18
(7x-19)-(5x-12)=3x-(9-2x)-1
cíu cíu tui zớiiiiiiiiii