mk ko btttttttttt

mk ko bt

troi  !

\(\left(2x-5\right)^5=\left(2x-5\right)^3\)

\(\left(2x-5\right)^5-\left(2x-5\right)^3=0\)

\(\left(2x-5\right)^3\left[\left(2x-5\right)^2-1\right]=0\)

\(\Rightarrow\orbr{\begin{cases}\left(2x-5\right)^3=0\\\left(2x-5\right)^2-1=0\end{cases}}\)    \(\Rightarrow\orbr{\begin{cases}2x-5=0\\\left(2x-5\right)^2=1=\left(\pm1\right)^2\end{cases}}\) \(\Rightarrow\orbr{\begin{cases}2x=5\\2x-5=-1\text{ hoặc }2x-5=1\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{5}{2}\\2x=4\text{ hoặc }2x=6\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=\frac{5}{2}\\x=2\text{ hoặc }x=3\end{cases}}\)

\(\Rightarrow\text{ }x\in\left\{\frac{5}{2}\text{ ; }2\text{ ; }3\right\}\)

\(\left(2x-5\right)^5=\left(2x-5\right)^3\)

=>\(\left(2x-5\right)^5-\left(2x-5\right)^3=0\)

=>\(\left(2x-5\right)^3.\left\{\left(2x-5\right)^2-1\right\}=0\)

=>\(\orbr{\begin{cases}\left(2x-5\right)^3=0\\\left(2x-5\right)^2-1=0\end{cases}}\)

=>\(\orbr{\begin{cases}2x-5=0\\\left(2x-5\right)^2=1\end{cases}}\)

=>\(x=\left\{\frac{5}{2};3;2\right\}\)\(\orbr{\begin{cases}x=\frac{5}{2}\\\orbr{\begin{cases}2x-5=1\\2x-5=-1\end{cases}}\end{cases}}\)

\(M=\left(-4x^2+2xy-\frac{y^2}{4}\right)-x^2+2x-1-\frac{3}{4}y^2+2y-2\)

\(M=-\left(4x^2-2\cdot2x\cdot\frac{y}{2}+\frac{y^2}{4}\right)-\left(x-1\right)^2-3\left(\frac{y^2}{4}-\frac{2y}{3}\right)-2\)

\(M=-\left(2x-\frac{y}{2}\right)^2-\left(x-1\right)^2-3\left(\frac{y^2}{4}-2\cdot\frac{y}{2}\cdot\frac{2}{3}+\frac{4}{9}-\frac{4}{9}\right)-2\)

\(M=-\left(2x-\frac{y}{2}\right)^2-\left(x-1\right)^2-3\left(\frac{y}{2}-\frac{2}{3}\right)^2+\frac{4}{3}-2\)

\(M\subseteq\frac{4}{3}-2=-\frac{2}{3}\)

Dấu = xr khi/.......

       m+(x+742)=(m+962)+742

=> m + x + 742 = m + 962 + 742

=> m + 742 + x = m + 742 + 962

=>                    x = 962 ( rút gọn m + 742 và m + 742 )

:v ủa phá ngoặc chuyển vế rồi tính thoi mà bạn :3

\(m+\left(x+742\right)=\left(m+962\right)+742.\)

\(m+x+742=m+962+742.\)

\(m-m+x=962+742-742\)

\(x=962\)

\(\Rightarrow x\in\left\{962\right\}\)

210 : [ 16 + 3 (6 + 3 . 2\(^2\)) - 3

= 210 :  70 -3

=  3  - 3

=0