Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Bài 1:
\(\frac{37.13-13}{24+37.12}=\frac{13.\left(37-1\right)}{2.12+37.12}=\frac{13.36}{12.\left(37+2\right)}=\frac{13.36}{12.39}=\frac{1.3}{1.3}=1\)
Bài 2:
\(\frac{101+100+...+2+1}{101-100+99-98+...+3-2+1}=\frac{\left[\left(101-1\right):1+1\right].\left(101+1\right):2}{\left(101-100\right)+\left(99-98\right)+...+\left(3-2\right)+1}\)\(=\frac{101.102:2}{1.\left[\left(101-1\right):2+1\right]}=\frac{5151}{1.51}=\frac{5151}{51}=101\)
\(\frac{3737.43-4343.37}{2+4+...+100}=\frac{37.101.43-43.101.37}{2+4+...+100}=\frac{0}{2+4+6+...+100}=0\)
1990.1990-1992.1998
=1990.1990-(1990+2).1998
=1990.1990-1990.1998+2.1998
=1990.(1990-1998)+2.1998
=1990.(-8)+2.1998
=1990.(-8)+2.(1990+8)
=1990.(-8)+2.1990+16
=1990.{(-8)+2}+16
=1990.(-6)+2.8
=(-1990).3.2+2.8
=-5970.2+2.8
=2.{(-5970)+8}
=2.-5962
=−11924
Bài 1:
a.1990.1990-1992.1988
Gọi 1990 là a ta có:
1992=a+2
1988=a-2
\(\Rightarrow A=a^2-\left(a+2\right)\left(a-2\right)\)
\(\Rightarrow A=a^2-a^2-2a+2a-4\)
\(\Rightarrow A=-4\)
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)
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
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/ \(=\frac{214.237+152}{870+\left(237-2\right).\left(124-2\right)}=\frac{124.237+152}{870+124.237-2.237-2.124+4}=\)
\(=\frac{124.237+152}{124.237+870+4-2.237-2.124}=\frac{124.237+152}{124.237+152}=1\)
ko có sai đâu mk cũng ko hiểu nếu hiểu đã ko cần hỏi rùi các bạ học giỏi ơi giúp mk với nha