Question

Choose the correct simplification of (2x3 + x2 − 4x) − (9x3 − 3x2).

11x3 − 2x2 − 4x
−7x3 + 4x2 − 4x
−2x3 − 2x2 − 4x
−7x3 − 4x2 − 4x

Answer 1

2x^3 + x^2 - 4x - (9x^3 - 3x^2) =
2x^3 + x^2 - 4x - 9x^3 + 3x^2 =
-7x^3 + 4x^2 - 4x <===

Answer 2

option (2) is correct.

`(2x^3+x^2-4x)-(9x^3-3x^2)=-7x^3+4x^2-4x`

Explanation:

Given expression
`(2x^3+x^2-4x)-(9x^3-3x^2)`

We have to choose the correct option that correctly simplify the given expression.

Consider the given expression
`(2x^3+x^2-4x)-(9x^3-3x^2)`

Opening the brackets , we get,

Applying plus-minus rule,
`-(-a)=+a`

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

LIKE TERMS are terms having same variable with same degree.

Adding like term , we get,

`(2x^3+x^2-4x)-(9x^3-3x^2)=(2-9)x^3+(3+1)x^2-4x`

`(2x^3+x^2-4x)-(9x^3-3x^2)=-7x^3+4x^2-4x`

Thus, option (2) is correct.