Find the zeros of y=x2-4x-9 by completing the square

x = 2 ±

Step-by-step explanation:

To find the zeros let y = 0, that is

x² - 4x - 9 = 0 ( add 9 to both sides )

x² - 4x = 9

To complete the square

add ( half the coefficient of the x- term )² to both sides

x² + 2(- 2) x + 4 = 9 + 4

(x - 2)² = 13 ← take the square root of both sides

x - 2 = ± ← add 2 to both sides

x = 2 ±

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation:

he sells x mount because thats eqivilqant to the maz and then divided into quarters

step-by-step explanation: