Select the correct answer.

What is the simplified form of this expression?
[tex]\ \textless \ br/\ \textgreater \ \left(-x^2+x\right)+\left(4 x^2-x-1\right)\ \textless \ br/\ \textgreater \ [/tex]

A. [tex] -3 x^2+1 [/tex]
B. [tex] 3 x^2-1 [/tex]
C. [tex] 3 x^2 -1 [/tex]
D. [tex] 5 x^2+2 x-1 [/tex]



Answer :

To simplify the given expression [tex]\(\left(-x^2 + x\right) + \left(4x^2 - x - 1\right)\)[/tex], we need to follow these steps:

1. Combine like terms by grouping the [tex]\(x^2\)[/tex] terms, the [tex]\(x\)[/tex] terms, and the constant terms separately.

The given expression is:
[tex]\[ \left(-x^2 + x\right) + \left(4x^2 - x - 1\right) \][/tex]

2. Combine the [tex]\(x^2\)[/tex] terms:
[tex]\[ -x^2 + 4x^2 = 3x^2 \][/tex]

3. Combine the [tex]\(x\)[/tex] terms:
[tex]\[ x - x = 0 \][/tex]

4. Combine the constant terms:
[tex]\[ -1 \][/tex]

5. Putting it all together, we get:
[tex]\[ 3x^2 + 0x - 1 \][/tex]
Simplifying the term [tex]\(0x\)[/tex], the expression becomes:
[tex]\[ 3x^2 - 1 \][/tex]

So, the simplified form of the expression is:

[tex]\[ 3x^2 - 1 \][/tex]

Therefore, the correct answer is:
[tex]\[ \boxed{3x^2 - 1} \][/tex]

Thus, the correct choice is:
[tex]\[ \text{B. } 3x^2 - 1 \][/tex]