a,1990.1990 - 1992 . 1988
b, (1374 . 57+687 .86) : (26.13+74.144)
c, (124.237+152) :(870+235.122)
d, \(\frac{423134.846267-423133}{846267.423133+423134}\)
K
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22 tháng 9 2023
a) 1990.1990 - 1992.1988
= 1990.1990 - (1990 + 2)(1990 - 2)
= 1990.1990 - 1990.1990 + 4 = 4
b) (1374.57 + 687.86) : (870 + 235.122)
= (1374.57 + 687.2.43) : (10.87 + 5.47.2.61)
= (1374.57 + 1374.43) : (10.87 + 10.47.61)
= [1374(57 + 43)] : [10(87 + 47.61)]
= (1374.100) : [10(87 + 47.61)] (đoạn này mẫu số xấu quá, hetcuu)
c) (124.237 + 152) : (870 + 235.122)
= (124.235 + 124.2 + 152) : (870 + 235.122)
= (122.235 + 2.235 + 2.124 + 152) : (870 + 235.122)
= (122.235 + 470 + 248 + 152) : (235.122 + 870)
= (122.235 + 870) : (235.122 + 870) = 1
d) \(\dfrac{423134\cdot846267-423133}{846267\cdot423133+423134}=\dfrac{423133\cdot846267+846267-423133}{846267\cdot423133+423134}\)
\(=\dfrac{423133\cdot846267+423134}{846267\cdot423133+423134}=1\)
12 tháng 11 2015
a)1990*1990-1992*1988=1990*(1988+2)-(1990+2)*1988=1990*1988+2*1990-1990*1988-2*1988=(1990*1988-1990*1988)+(2*1990-2*1988)=0+2*(1990-1988)=2*2=4
b)(1374*57+687*86)/(26*13+74*14)=(687*2*57+687*86)/(26*13+74+74*13)=(687*114+687*86)/(100*13+74)
=(687*200)/1374=137400/1374=100
c)(124*237+152)/(870+235*122)=\(\frac{\left(122+2\right)\cdot237+152}{870+\left(237-2\right)\cdot122}=\frac{122\cdot237+2\cdot237+152}{870-2\cdot122+237\cdot122}=\frac{122\cdot237+626}{626+237\cdot122}=1\)
d)\(\frac{423134\cdot846267-423133}{846267\cdot423133+423134}=\frac{\left(423133+1\right)\cdot846267-423133}{846267\cdot423133+423134}\)
\(=\frac{423133\cdot846267+846267-423133}{846267\cdot423133+423134}=\frac{423133\cdot846267+423134}{846267\cdot423133+423134}=1\)
(mỏi hết cả mắt)
10 tháng 9 2015
a)1990.1990+1992.1988
=3960100+3960096
=7920196
b)(124.237+152):(870+235.122)
=(29388+152):(870+28670)
=29540:29540
=1
c)(423134.846267-423133):(846267.423133+423134)
=(423134.846267):(423133-423134)
=(423134.846267):0
=0
26 tháng 9 2016
a)
1990.1990 -1992.1998 = (1995-5)^2 -(1995+3)(1995-3) = -10.1995 +25 +9 = -(19950-34) = -19916
b)
ta có
tu = 124 .237 +152 = 122.137 + 474 +152= 122. 137 + 626
mau = ( 870 + (237-2).122= 870 +122.237 - 244 =122.237 + 626
=> phân thức đã cho = tử/mẫu = 1
NN
26 tháng 9 2016
a/ \(=1990.1990-\left(1990+2\right).\left(1990-2\right)=1990.1990-\left(1990.1990-4\right)=4\)
b/ \(=\frac{2.687.57+687.86}{26.13+74.\left(13+1\right)}=\frac{687\left(2.57+86\right)}{26.13+74.13+74}=\frac{687.\left(114+86\right)}{13\left(26+74\right)+74}=\)
\(=\frac{687.200}{13.100+74}=\frac{687.200}{1374}=\frac{687.200}{687.2}=\frac{200}{2}=100\)
c/ \(=\frac{214.237+152}{870+\left(237-2\right).\left(124-2\right)}=\frac{124.237+152}{870+124.237-2.237-2.124+4}=\)
\(=\frac{124.237+152}{124.237+870+4-2.237-2.124}=\frac{124.237+152}{124.237+152}=1\)
