rút gọn a,( x+y-z)^2 +(x-y)^2+2(x-y) (x+y-z) 23/09/2021 Bởi Liliana rút gọn a,( x+y-z)^2 +(x-y)^2+2(x-y) (x+y-z)
\[\begin{array}{l} {\left( {x + y – z} \right)^2} + {\left( {x – y} \right)^2} + 2\left( {x – y} \right)\left( {x + y – z} \right)\\ = {\left( {x + y – z + x – y} \right)^2}\\ = {\left( {2x – z} \right)^2}. \end{array}\] Bình luận
Ta có:
(x+y−z)^2+(x−y^)2+2(x−y)(x+y−z)
=(x+y−z+x−y)^2
=(2x−z)^2
\[\begin{array}{l}
{\left( {x + y – z} \right)^2} + {\left( {x – y} \right)^2} + 2\left( {x – y} \right)\left( {x + y – z} \right)\\
= {\left( {x + y – z + x – y} \right)^2}\\
= {\left( {2x – z} \right)^2}.
\end{array}\]