Explanation:
16-9x² must be greater than 0
So 16-9x²>0
We can't solve it like this so we will write it like an equation
16-9x²=0
-9x²=-16
9x²=16
X²=1.77
X= -1.33 and +1.33
We will pulg a number greater than 1.33 and a number between +1.33 and - 1.33
First one (2)
16-9(2)²
It equals - 20 so it can't be true because there is not a root for - 20 in real numbers
And the second number we will try is (1)
16-9(1)
It equals +7 so it is true
Then the domain is - 1.33≤ x≤1.33
Because if you plug 1.33 in the function it will also give you a real number
Hope it helps