Question

Hey can you please help me posted picture of question

Answer 1

X^2-81=0
x^2-81+81=0+81
x^2=81
sqrt(x^2)=+-sqrt(81)
x=+-9
x=-9 and x=9

Answer: Options D. -9  and E. 9

Answer 2

Answer:
The roots are 9 and -9

Explanation:
Before we begin, remember the rule of the difference between squares which is as follows:
a² - b² = (a+b)(a-b)

Now, for the given:
x² - 81 = 0
This can be rewritten as:
x² - (9)² = 0
Applying the rule of the difference between squares, we can factor this expression as follows:
(x-9)(x+9) = 0

This means that:
either x-9 = 0 ..........> x = 9
or x+9 = 0 ..........> x = -9

Hope this helps :)