`A=6x^2-3xy^2` `B=x^2+y^2-2xy^2` Tính `A+B` ; `A-B`

0 bình luận về “`A=6x^2-3xy^2` `B=x^2+y^2-2xy^2` Tính `A+B` ; `A-B`”

1. \(\begin{array}{l}
   A = 6x^2 – 3xy^2\\
   B = x^2 + y^2 – 2xy^2\\
   +)\quad A  + B = 6x^2 – 3xy^2 + x^2 + y^2 – 2xy^2\\
   \Leftrightarrow A + B = (6x^2 + x^2) – (3xy^2 + 2xy^2) + y^2\\
   \Leftrightarrow A + B = 7x^2 – 5xy^2 + y^2\\
   +)\quad A – B = 6x^2 – 3xy^2 – (x^2 + y^2 – 2xy^2)\\
   \Leftrightarrow A – B = (6x^2 – x^2) – (3xy^2 – 2xy^2) – y^2\\
   \Leftrightarrow A – B = 5x^2 – xy^2 – y^2
   \end{array}\)

    

   Bình luận

2. Đáp án:

    $A=6x^2 -3xy^2$

   $B=x^2 +y^2 -2xy^2$

   $A+B$

   $=6x^2 -3xy^2 +x^2+y^2-2xy^2$

   $=7x^2 +y^2-5xy^2$

   $A-B$

   $=6x^2 -3xy^2 -(x^2+y^2 -2xy^2)$

   $=6x^2 -3xy^2 -x^2 -y^2 +2xy^2$

   $=5x^2 -y^2 -xy^2$

   Bình luận