Simplify the expression by adding or subtracting the polynomials: \( \left(-4 x^{3}+8 x^{2}+6 x+8\right)-\left(5 x^{3}+6 x^{2}+9 x-3\right)+\left(-9 x^{3}-x^{2}-3 x+7\right) \) The expression simplifies to Ehter your answer Submit answer Attemnts. \( 0 / 5 \)

To simplify the given expression, let's first distribute the negative sign in the second polynomial and then combine like terms: \[ \left(-4x^3 + 8x^2 + 6x + 8\right) - \left(5x^3 + 6x^2 + 9x - 3\right) + \left(-9x^3 - x^2 - 3x + 7\right) \] This expands to: \[ -4x^3 + 8x^2 + 6x + 8 - 5x^3 - 6x^2 - 9x + 3 - 9x^3 - x^2 - 3x + 7 \] Now, combine the coefficients of like terms: 1. For \(x^3\): \(-4 - 5 - 9 = -18x^3\) 2. For \(x^2\): \(8 - 6 - 1 = 1x^2\) 3. For \(x\): \(6 - 9 - 3 = -6x\) 4. For the constant term: \(8 + 3 + 7 = 18\) Putting it all together: \[ -18x^3 + 1x^2 - 6x + 18 \] Thus, the simplified expression is: \(-18x^3 + x^2 - 6x + 18\)