Question

Thu gọn đa thức sau:

Q = x² + y² + z² + x² - y² + z² + x² + y² - z²

Answer 1

Q = x² + y² + z² + x² - y² + z² + x² + y² - z².

Q = (x² + x² + x² ) + (y² - y² + y²) + (z² + z² - z²)

= 3x² + y² + z².

Answer 2

Q = x² + y² + z² + x² - y² + z² + x² + y² - z².

Q = (x² + x² + x² ) + (y² - y² + y²) + (z² + z² - z²)

= 3x² + y² + z².

Answer 3

Q = x2  + y2  + z2  + x2 – y2  + z2  + x2   + y2  - z2
= x2 + x2  + x2  + y2 + y2  - y2 + y2 + z2  + z2 - z2
= 3x2 + y2 + z2

Answer 4

Q = x² + y² + z² + x² - y² + z² + x² + y² - z²

Q=(x²+x²+x²)+(y²-y²+y²)+(z²+z²-z²)

=3x²+y²+z²