4. (5x^2 - 4x -1) - (-4x^2 -4) (1 point)
-9x^2 - 8x - 1
9x^2 - 4x + 3
x^2 - 4x - 3
9x^2 + 4x - 3
9x^2 - x - 3
That's not one of the answers
I apologize. I made a mistake in my calculation. The correct answer is:
9x^2 - 4x - 3
To simplify the expression (5x^2 - 4x - 1) - (-4x^2 - 4), let's first distribute the negative sign to all terms within the parentheses:
= 5x^2 - 4x - 1 + 4x^2 + 4
Next, combine like terms by adding or subtracting coefficients of the same degree:
= (5x^2 + 4x^2) + (-4x) + (4 - 1)
= 9x^2 - 4x + 3
Therefore, the simplified expression is 9x^2 - 4x + 3.