Factoring a basic trinomial using the x method, x^2 + 8x - 9

The video tutorial explains the process of factoring a quadratic expression. It guides students through identifying two numbers that multiply to a given product and add to a specific sum. The teacher provides helpful hints, such as ensuring one number is negative when the product is negative, and the larger number is positive when the sum is positive. The tutorial concludes with the factored form of the expression and emphasizes the simplicity of the process.

What are the two possibilities for the numbers that multiply to give you 9?

Why must one of the numbers be negative when factoring to achieve a positive sum?