9) 4x2-7x4-(2x²-4x1-x2) + (-x^3 + x) = 2x-300+00²³+x²

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

$$ 4x^2 - 7x^4 - 2x^2 + 4x^4 + x^3 - x^3 + x = -3x^4 + 2x^2 + x$$

Ответ: $$-3x^4 + 2x^2 + x$$