B1:
a)(2√6 - 4√3+5√2 -¼√8).3√6
b)(³√9/5 - 3.³√9/5 +4³√1/3 ):
2³√1/3
Giup mk vs mk dg can gap
a) 7/-25+8/25 ; 4/5+4/-18 ; 7/21+9/-36
b) 12/20-2/5 ; 2/3-(-5/6) ; 6-3/20
c)2/21*(-7/3) ; 27/28*(-21) ; -15/7*(-14/25)
ai nhanh mk tk cho giup k nhe minh can gap
2 * 3 * 4 * 5 phan 6 * 7 * 8 * 9
GIUP MH VOI
MK CAN GAP
2x3x4x5/6x7x8x9
=6x20/42x72
=120/3024
=5/126
mk nha
a.3/4-[1/2+4/7]×1/4
b.8/9-[1/2+1/2:1/4]×1/3
c.4/5×1/3+4/5×2/9
d.6 1/3:1 6/11-1 2/17 ×1 1/3
e.2và 1/7 +3và1/5×2 và 1/2
giúp mk vs mk đang cần gấp ai đúng mk tick nha
1+1+2+2+3+3+4+4+5+5+6+6+10+10+12+12+14+14+16+16+18+18+20+20+7+7+8+8+9+9
GIUP MK VOI MK TICK CHO NGUOI NHANH NHAT
1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9=2+4+6+8+10+12+14+16+18
=(2+8)+(4+6)+10+(12+18)+(14+16)
=10+10+10+30+30
=30+30+30
=30x3
=90
1.tinh nhanh
(-24)-(-6)-(-10)-(-24)
b) 15-(23)-25-23
c) (-3)-350-7-(-350)
d) (-9)-11+21-1
2...tinh tong
12:48
a) a=1+(-2)+(-3)+4+5+(-6)+(-7)+8+.............+(-1997)+1998)+(-1999)+2000
b) b=2+(-4)+6+(-8)+...........+1998+(-2000)+2002
c) c=1-3+5-7+.......+1995+1997+1999
m..n oi giup ti di ak mk dang can gap lam
bai 1 tinh nhanh
a . 1/5x6 +1/6x7+ 1/7x8 + 1/8x9 +1/9x10
b . 1/1x2 + 1/2x3 + ....... + 1/99x100
c . 2/3x5 + 2/5x7 + 2/7x8 + 2/8x9
d . 2/3x5 + 2/5x7 + .......+ 2/98x100
bai 2 tinh hop li
9/13 + 14/6 + 1/9 + 4/6 + 7/13 + 17/19
bai 3 dien dau ( > , < , = )
a . 3/4 + 5/2 ....... 5/8 + 2 3/5 ( hon so )
B . 3 1/5 - 8/3 ......... 17/5 - 2 12/5 hon so
c . 2 4/9 + 18/7......... 22/9 + 2 4/7
giup mk nha cac ban , mai mk phai nop bai roi toi nay mk se lay y kien cua cac ban , giup mk nha
b1
a) \(\dfrac{1}{5.6}+\dfrac{1}{6.7}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}\)
\(=\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}\)
\(=\dfrac{1}{5}-\dfrac{1}{10}\)
\(=\dfrac{2}{10}-\dfrac{1}{10}\)
\(=\dfrac{1}{10}\)
b) \(\dfrac{1}{1.2}+\dfrac{1}{2.3}+...+\dfrac{1}{99.100}\)
\(=\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{99}-\dfrac{1}{100}\)
\(=\dfrac{1}{1}-\dfrac{1}{100}\)
\(=\dfrac{99}{100}\)
c) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+\dfrac{2}{7.9}+\dfrac{2}{9.11}\)
\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{11}\)
\(=\dfrac{1}{3}-\dfrac{1}{11}\)
\(=\dfrac{8}{33}\)
d) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+...+\dfrac{2}{99.101}\)
\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{99}-\dfrac{1}{101}\)
\(=\dfrac{1}{3}-\dfrac{1}{101}\)
\(=\dfrac{98}{303}\)
A=5/9 - 7/8 + 2/3 + 4/9 - 1/8 + 1/3
B= 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42
a) Tính A và B
b) Tìm C bíêt ( A - 7B) cua C bang 2010
Cau A và B mk dã giai roi , cau A ra 1, B ra 6/7 ,cac bn chi can giup mk cau C thoi , cauC mk ko bt cach giai!!!
Bn nao giup mk , mk se tick.
1 * 2 * 3 *4 phan 5 * 6 * 7 * 8
moi nguoi oi giup mk nha
mk can gap
dau * la dau nhan nhe
\(\frac{1\times2\times3\times4}{5\times6\times7\times8}\)
\(=\frac{1\times2\times3\times4}{5\times2\times3\times7\times4\times2}\)
\(=\frac{1}{5\times7\times2}\)
\(=\frac{1}{70}\)
\(\frac{1\times2\times3\times4}{5\times6\times7\times8}=\frac{6\times4}{6\times5\times7\times4\times2}=\frac{1}{5\times7\times2}=\frac{1}{70}\)
1+2+3+4+5+6+7+8+9+1+2+3+4+5+6+7+8+9+1+2+3+4+5+6+7+8+9 +1028 giúp mk nha
1+2+3+4+5+6+7+8+9+1+2+3+4+5+6+7+8+9+1+2+3+4+5+6+7+8+9+1028=(1+2+3+4+5+6+7+8+9)x3+1028=45x3+1028=135+1028=1163
= ( 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 ) x 3 +1028
\(=\) \(\frac{9.\left(9+1\right)}{2}\times3+1028\)
\(=45\times3+1028\)
\(=135+1028=1163\)