A real numbers are numbers that can be found on a number line, they include both rational and irrational numbers.
We can first solve the equation;
x² - 6x + 9 =0, using completing square method;
x²- 6x + (-3)² = -9 + (-3)²
(x-3)² = 0
x = 3
therefore, both values of x are 3, thus the expression has no real number x is negative.