Question

Which choice is the conjugate of the expression below when x >= 6?

sqrt x-6-3

A.sqrt x-6+3
B.sqrt x+6+3
C.sqrt x-6-3
D.sqrt x+6-3

Answer 1

Option A)
`√(x-6) +3`

Explanation:

Given is an expression in x as

`√(x-6) -3`

This will be real only for x>=6

(That is given already)

Now to find conjugate

Since x-6 is inside root sign, we can take this as one term.

Next term is -3. To find conjugate we write the root sign term as it is and change the sign of next term from negative to positive

i.e. -3 becomes +3

Hence conjugate would be

`√(x-6) +3`

Hence option A is right