Toán Lớp 8: Helppp
a) Biết (a+b)^2=4ab, chứng minh rằng a=b
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 8: Helppp
a) Biết (a+b)^2=4ab, chứng minh rằng a=b
Comments ( 2 )
{(a + b)^2} = 4ab\\
\Leftrightarrow {a^2} + 2ab + {b^2} = 4ab\\
\Leftrightarrow {a^2} + {b^2} = 4ab – 2ab\\
\Leftrightarrow {a^2} + {b^2} = 2ab\\
\Leftrightarrow {a^2} – 2ab + {b^2} = 0\\
\Leftrightarrow {(a – b)^2} = 0\\
\Leftrightarrow a – b = 0\\
\Leftrightarrow a = b\\
{(a + b)^2} = 4ab \Rightarrow a = b
\end{array}\]