Could someone kindly help me in finding a solution?

see explanation

Step-by-step explanation:

(a)

= =

Substitute x = - 1 into the expression

(- 1 ) = = = = -

(b)

The denominator of cannot be zero as this would make undefined

To find the values that x cannot be , equate the denominator to zero and solve for x

(x - 2)(x + 2) = 0

x - 2 = 0 ⇒ x = 2

x + 2 = 0 ⇒ x = - 2

values that are not in the domain of : x = - 2, x = 2

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

72 is the answer to this problem