Answer:
The value of k for the expression to be undefined is 9 .
Step-by-step explanation:
Given as :
The rational expression is written in the form
Now, according to question
The expression to be undefined , denominator should be 0
<u>As, is infinite ( ∞ ) term and it is undefined , so for expression to be undefined , the denominator should be 0</u>
∴ k² - 18 k + 81 = 0
Or, k² - 9 k - 9 k + 81 = 0
Or, k ( k - 9 ) - 9 ( k - 9) = 0
Or, ( k - 9 ) ( k - 9 ) = 0
Or, ( k - 9 ) = 0 , ( k - 9 ) = 0
∴ k = 9
So, The value of k = 9
Hence The value of k for the expression to be undefined is 9 . Answer