Question

Cmr: Nếu a²+b²=2ab thì a=b

Answer 1

a²+b²=2ab

aa+bb=2ab

aa+bb-2ab=0

=>a=b=0

Answer 2

a²+b²=2ab

=> a²+b²  - 2ab= 0

=> \(\left(a-b\right)^2=0\)

=> a-b = 0

=> a= b [đpcm]

Answer 3

a^2 + b^ 2 = 2ab

=>a^2+b^2- 2ab = 0

=> ( a-b) ^{^2}  =0 

=> a-b=0

=> a=b ( đpcm )

 

 

Answer 4

\(a^2+b^2=2ab\)

\(\Leftrightarrow\left(a-b\right)^2=0\) (luôn đúng)

Dấu " = " xảy ra \(\Leftrightarrow a=b\)