Final answer:
To address the question, one must solve quadratic equations and inequalities using the quadratic formula or by completing the square, depending on the form of the equation.
Step-by-step explanation:
The question provided contains an incorrect function notation and seems to reflect a series of mathematical typos, making it difficult to address as asked.
However, from the additional information, I gather that we need to solve a quadratic inequality and also solve quadratic equations using the quadratic formula.
Let's address the general concept of solving quadratic equations.
To solve a quadratic equation of the form ax² + bx + c = 0, where 'a', 'b', and 'c' are constants, we can use the quadratic formula:
x = ∛(-b ± √(b² - 4ac)) / (2a)
This formula allows us to find the roots of the quadratic equation. For inequalities like ax² + bx + c ≤ 0 or ax² + bx + c ≥ 0, we find the roots using the quadratic formula and then determine the intervals where the inequality holds true.
Remember, completing the square is another method to solve quadratics and is particularly useful when the equation is in a form that makes it convenient.