Which expression is equivalent to `\left(4\ -\ 2x^{2}\ -\ 5x\right)+\left(5x^{2}\ -\ 9\ +\ 3x\right)`?

Answer 1

To simplify this expression, we can combine like terms:

`(4 - 2x^2 - 5x) + (5x^2 - 9 + 3x)`

Combine the terms inside the parentheses:

`= 4 - 2x^2 - 5x + 5x^2 - 9 + 3x`

Rearrange the terms to group the like terms together:

`= (4 - 9) + (-2x^2 + 5x^2 - 5x + 3x)`

Combine the constants and the coefficients of x terms:

`= -5 + 3x - 2x^2 + 5x^2`

Combine the x^2 term and the x term:

`= 3x - 2x^2 + 5x^2 - 5`

Therefore, the expression is equivalent to `5x^2 - 2x^2 + 3x - 5`, which can also be written as `3x^2 + 3x - 5`.