(27)

The function is

To find the values of x such that f(x) = 4

Let f(x) = 5-x

(28)

The system of equation are given in matrix form

The augmented matrix is

now apply

As the rank of Augmented matrix = 3

Rank of the Matrix A is 3

Rank of A = Rank of [A|B] then it has finite solutions

From the augmented matrix,we can say

z = 9

y = 5

-2x+8y + z = 1

-2x + 8*5 + 9 = 1

-2x = -48

x = 24

Therefore the solutions are

Option (d) is the correct answer.