\(63^2-47^2\)

= \(\left(63-47\right)\left(63+47\right)\)

= \(16.110\)

= \(1760\)

a) \(63^2-47^2=\left(63-47\right)\left(63+47\right)=16\cdot110=1760\)

b) \(215^2-105^2=\left(215-105\right)\left(215+105\right)=35200\)

c) \(437^2-363^2=59200\)

d) \(537^2-463^2=74000\)

a,1/20

b,4/5

mình chưa học lớp 8

có cần bạn bình luận vậy ko 

\(A=\frac{63^2-47^2}{215^2-105^2}=\frac{\left(63+47\right)\left(63-47\right)}{\left(215+105\right)\left(215-105\right)}=\frac{110\cdot16}{320\cdot110}=\frac{1}{20}\)

\(B=\frac{437^2-363^2}{537^2-463^2}=\frac{\left(473-363\right)\left(473+363\right)}{\left(573-463\right)\left(573+463\right)}=\frac{110\cdot836}{110\cdot1036}=\frac{836}{1036}=\frac{4\cdot209}{4\cdot234}=\frac{209}{234}\)

Trả lời:

\(A=\frac{63^2-47^2}{215^2-105^2}=\frac{\left(63-47\right).\left(63+47\right)}{\left(215-105\right).\left(215+105\right)}=\frac{16.110}{110.320}=\frac{1}{20}\)

\(B=\frac{437^2-363^2}{537^2-463^2}=\frac{\left(437-363\right).\left(437+363\right)}{\left(537-463\right).\left(537+463\right)}=\frac{74.800}{74.1000}=\frac{4}{5}\)

Học tốt 

Áp dụng HĐT số 3 bạn nhé '-'

\(A=\frac{63^2-47^2}{215^2-105^2}=\frac{\left(63+47\right)\left(63-47\right)}{\left(215+105\right)\left(215-105\right)}=\frac{110\cdot16}{320\cdot110}=\frac{16}{320}=\frac{1}{20}\)

\(B=\frac{437^2-363^2}{537^2-463^2}=\frac{\left(437+363\right)\left(437-363\right)}{\left(537+463\right)\left(537-463\right)}=\frac{800\cdot74}{1000\cdot74}=\frac{800}{1000}=\frac{8}{10}=\frac{4}{5}\)

\(\frac{63^2-47^2}{215^2-105^2}=\)  \(\frac{\left(63-47\right)\left(63+47\right)}{\left(215-105\right)\left(215+105\right)}\)

                           \(=\frac{16.110}{110.320}=\frac{16}{320}\)\(=\frac{1}{20}\)

các câu kia làm tương tự nha

Thanks bạn nhiều nhiều nha!

nhưng câu d với câu e mk khô hiểu lắm!

B3. 
a) =\(\frac{\left(63+47\right).\left(63-47\right)}{\left(215+105\right).\left(215-105\right)}\)               b) =\(\frac{\left(437+363\right).\left(437-363\right)}{\left(537+463\right).\left(537-463\right)}\)
  =\(\frac{110.16}{320.110}\)                                                   =\(\frac{800.74}{1000.74}\)
  =\(\frac{1}{20}\)                                                             =\(\frac{4}{5}\)

A=\(\frac{63^2-47^2}{215^2-105^2}\)

A=\(\frac{\left(63-47\right).\left(63+47\right)}{\left(215-105\right).\left(215+105\right)}\)

A=\(\frac{16.110}{110.320}\)

A=\(\frac{1760}{35200}\)

\(A=\frac{1}{20}\)

B=\(\frac{437^2-363^2}{537^2-463^2}\)

B=\(\frac{\left(437-363\right).\left(437+363\right)}{\left(537-463\right).\left(537+463\right)}\)

B=\(\frac{74.800}{74.1000}\)

B=\(\frac{4}{5}\)

Bài 1 :

\(A=26^2-24^2=\left(26-24\right)\left(26+24\right)=2.50=100\)

\(B=27^2-25^2=\left(27-25\right)\left(27+25\right)=2.52=104\)

Vì \(100< 104\Rightarrow A< B\)

Bài 2 :

\(4\left(x+1\right)^2+\left(2x-1\right)^2-8\left(x-1\right)\left(x+1\right)=11\)

\(\Rightarrow4\left(x^2+2x+1\right)+4x^2-4x+1-8\left(x^2-1\right)=11\)

\(\Rightarrow4x^2+8x+4+4x^2-4x+1-8x^2+8=11\)

\(\Rightarrow4x=-2\)\(\Leftrightarrow x=-\frac{1}{2}\)