What is the form of the difference of squares identity?

The difference identity of two squares can be stated as:

a² - b² = (a + b)(a -b)

i.e. the product of sum of two numbers with the difference of two numbers. This can be easily proved.

For example, Let a = 4 and b = 3

so, a² - b² = 16 - 9 = 7

a + b = 4 + 3 = 7
a - b =4 - 3 = 1

(a + b )(a - b) = 7 x 1  = 7

Thus,

a² - b² = (a+b)(a-b)

So, option C gives the correct answer

r   = 2.65m

good luck!

cutie~