kx+y=1, x+ky=2

Question

solve for k
the answer is one of the following choices:

A) K=1
B) K=-1
C) K=1 and K= -1
D) K is not equal to 1, -1

Answer 1

Given equations are kx+y =1

x+ky =2

Carmers rule AX=B

Here A is coefficient matrix, X is varible matrix and B is constant matrix.

Convert the equations into matrices form.

Substitute k =1in x.y values

x =1-2/1-1 = -1/0

y = 2-1/1-1 = 1/0

these are not defined.

Substitute k =-1 in x,y values.

x =-3/0

y = -3/0

these are also not defined.

So k is not equal to 1,-1

Option D is correct answer.