Understanding Polynomial Roots and Theorems
Ever wondered where a graph crosses the x-axis? Those points are called roots or zeros of a polynomial function. For example, the function f(x) = x³ - 2x² - 5x + 6 has zeros at -2, 1, and 3.
Before diving into new concepts, let's review factoring. When we factor a polynomial like 2x² + 8x + 6, we get 2x+1x+3. The factors directly connect to the zeros—if x−2 is a factor, then 2 is a zero!
The Remainder Theorem gives us a cool shortcut: When you divide a polynomial f(x) by x−r, the remainder equals f(r). For instance, if you divide 4x² - 3x + 6 by x−2, the remainder is 16, which is exactly what you get when you calculate f(2).
💡 Quick Tip: To check if a number might be a zero of a polynomial, just plug it in! If f(r) = 0, then x−r is definitely a factor of your polynomial.
This relationship between factors and zeros makes solving polynomial equations much easier once you understand the pattern.