so sanh A va B biet:
A=2.005 x 200.5 B=2.004 x 20.06
so sanh a va b biet:
a, A= 198719871987 x 1988198819881988,
B= 198819881988 x 1987198719871987,
b, 19,91 x19,99 va 19,95 x 19,95
hay so sanh A va B biet :
A = x7y + 3,m6 va B + x,my + 3,76
ko tinh cu the, hay so sanh a va b biet
a = 2002 x 2002
b = 2002 x 2004
a = 2002 x 2002
b = 2002 x 2004
Vì 2002<2004 vậy a<b
Vì 2002 = 2002
Mà 2002 < 2004
=> 2002.2002 < 2002.2004
a = 2002 x 2002
b = 2002 x 2004
=> a < b
*******************************
Bai 1.Tim x, y biet :
2x(3y-2)+(3y-2) = -55
Bai 2 .a) So sanh : -22/45 va -51/103
b) So sanh A = 2009^2009 +1 / 2009^2010 va B = 2009^2010-2/2009^2011-2
Bai 3 :
a)Tim so tu nhien co 3 chu so , biet rang khi chia so do cho cac so 25, 28,35thi duoc cac so du lan luot la 5,8,15
b)Tim x: (x+1)+(x+2)+(x+3)+...+(x+100)=205550
cho a,b,m e N , b, m # 0
a, biet a/b <1 . hay so sanh a/b va a+m/b+m
b, biet a/b >1 . hay so sanh a/b va a+m/b+m
khong quy dong tu so va mau so hay so sanh
a) 13/17 va 15/19
tim x biet
a) \(\frac{2}{3}\times x+\frac{3}{4}=3\)
b, 720:[41-(2x x-5)]=120
a)13/17 < 15/19
a) 2/3 x X + 3/4 = 3
2/3 x X = 3 - 3/4
2/3 x X = 9/4
X = 9/4 : 2/3
X = 27/8
a. Ta có : \(\frac{13}{17}=\frac{247}{323};\frac{15}{19}=\frac{255}{323}\)
Vì 255 > 247 nên 247/323 < 255/323
Hay \(\frac{13}{17}< \frac{15}{19}\)
b. \(\frac{2}{3}\times x+\frac{3}{4}=3\)
\(\frac{2}{3}\times x=3-\frac{3}{4}\)
\(\frac{2}{3}\times x=\frac{9}{4}\)
\(x=\frac{9}{4}:\frac{2}{3}\)
\(x=\frac{27}{8}\)
c. \(720:\left[41-\left(2\times x-5\right)\right]=120\)
\(\left[41-\left(2\times x-5\right)\right]=720:120\)
\(41-\left(2\times x-5\right)=6\)
\(2\times x-5=35\)
\(2\times x=40\)
\(x=20\)
a)\(\frac{13}{17}>\frac{15}{19}\)
b)\(720\div[41-(2x\times5)]=120\) c)\(\frac{2}{3}\times x+\frac{3}{4}=3\)
\(41-(2x\times5)=270\div120\) \(\frac{2}{3}\times x=3-\frac{3}{4}\)
\(41-(2x-5)=6\) \(\frac{2}{3}\times x=\frac{9}{4}\)
\(2x-5=41-6\) \(x=\frac{9}{4}\div\frac{2}{3}\)
\(2x-5=35\) \(x=\frac{9}{4}\times\frac{3}{2}\)
\(2x=35+5\) \(x=\frac{27}{8}\)
\(2x=40\)
\(x=40\div2\)
\(x=20\)
so sanh a va b biet a=1995x1995 b=1994x1996
A=1995*1995 B=1994*1996
A=(1994+1)*1995 B=1994*(1995+1)
A=1994*1995+1*1995 B=1994*1995+1*1994
Vì 1994*1995=1994*1995 ; 1*1995 > 1*1994
Nên 1995*1995 > 1994*1996
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
so sanh -58/89 va 36/-53
tim x thuoc z biet
a) 2x+7 chia het x+3
b) x^2 +5x+11 chia hetx+3
Có \(\frac{36}{-53}\) = \(\frac{-36}{53}\)
Lại có -58 < -36 => \(\frac{-58}{89}\) < \(\frac{-36}{53}\) hay \(\frac{-58}{89}\) < \(\frac{36}{-53}\)
tuổi con HN là :
50 : ( 1 + 4 ) = 10 ( tuổi )
tuổi bố HN là :
50 - 10 = 40 ( tuổi )
hiệu của hai bố con ko thay đổi nên hiệu vẫn là 30 tuổi
ta có sơ đồ : bố : |----|----|----|
con : |----| hiệu 30 tuổi
tuổi con khi đó là :
30 : ( 3 - 1 ) = 15 ( tuổi )
số năm mà bố gấp 3 tuổi con là :
15 - 10 = 5 ( năm )
ĐS : 5 năm
mình nha
so sanh A va B biet :A=2011^2012-2011^2011 va b=2011^2013-2011^2012