What is first order derivative?

The first order derivative of a function represents the rate of change of one variable with respect to another variable. For example, in Physics we define the velocity of a body as the rate of change of the location of the body with respect to time.

answer:   x = 3 + √11     and     x = 3 - √11

step-by-step explanation:

x² - 6x + 9 = 11

(x - 3)² = 11

x - 3 = ±√11

    x = 3 ± √11

x = 3 + √11     and     x = 3 - √11