Question

Perform the operation indicated, then place the answer in the proper location on the grid. Write your answer in descending powers of m. (5m 3 + 3mn 2) + (-7m 2n + mn 2 - n 3) - (mn 2 + 2m 3)

Answer 1

The given expression in descending powers of m is

`{\bf 3m^3+3m^2n-7m^2n-n^3}`

Explanation:

The given expression is
`(5m^3+3mn^2)+(-7m^2n+mn^2-n^3)-(mn^2+2m^3)`

Now solve the above expression

`(5m^3+3mn^2)+(-7m^2n+mn^2-n^3)-(mn^2+2m^3)=5m^3+3mn^2-7m^2n+mn^2-n^3-mn^2-2m^3`

`(5m^3+3mn^2)+(-7m^2n+mn^2-n^3)-(mn^2+2m^3) = 3m^3+3m^2n-7m^2n-n^3` (where
`mn^2` and
`-mn^2` getting cancelled because of alternate signs)

Therefore the above expression in descending powers of m is

`3m^3+3m^2n-7m^2n-n^3`