hay so sanh A va B biet :
A = x7y + 3,m6 va B + x,my + 3,76
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
biet a<b hay so sanh 5-2a va 3-2a
a<b nên -a>-b có 5>3 nên 5+(-a)>3+(-b) hay rút gọn được 5-a>3-b
1 LÌKEnhé
khong tinh gia tri cua a va b hay so sanh a va b va tinh hieu cua chung biet rang.
A=2004.2005
B=2000.2009
A = 2004.2005
= (2000 + 4).2005
= 2000.2005 + 4.2005
B = 2000.2009
= 2000.(2005 + 4)
= 2000.2005 + 2000.4
=> A > B
@Nguyễn Hoàng Nina
Khong tinh gia tri cua a va b. Hay so sanh a va b. Biet:
a bang 2136.2136
b bang 2134.2138
a=b
vì : b=2134.2138=(2134+2).(2138-2) = 2136.2136 =a
Ta có:
a = \(2136\times2136=\left(2134+2\right)\times2136=2134\times2136+2\times2136\)
b = \(2134\times2138=2134\times\left(2136+2\right)=2134\times2136+2134\times2\)
Vì \(2134\times2136=2134\times2136\)và\(2136\times2>2134\times2\)nên a > b.
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
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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)\(\frac{2}{3}\times x+\frac{3}{4}=3\)
\(41-(2x\times5)=270\div120\) \(\frac{2}{3}\times x=3-\frac{3}{4}\)
\(41-(2x-5)=6\) \(\frac{2}{3}\times x=\frac{9}{4}\)
\(2x-5=41-6\) \(x=\frac{9}{4}\div\frac{2}{3}\)
\(2x-5=35\) \(x=\frac{9}{4}\times\frac{3}{2}\)
\(2x=35+5\) \(x=\frac{27}{8}\)
\(2x=40\)
\(x=40\div2\)
\(x=20\)
Khong tinh hay so sanh A va B biet
A = 2000 . 2000 va B= 2001 . 1990
A= 27 . 58 - 31 va B= 27+ 58 . 28
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 = a,53 + 4,b6 + 2, 9c
b = a,bd + 8,3c - 0,8d