## anonymous one year ago Just a quick clarification? (Problem in comments.)

1. anonymous

I need to find the conjugate of $a-\sqrt{a-1}$

2. misssunshinexxoxo
3. anonymous

I'm not sure if it is $a+\sqrt{a+1}$ or $a-\sqrt{a-1}$ the lesson I had is not very clear.

4. anonymous

I just need to know if when flipping the sign I flip the sign on the inside of the radical?

5. mathstudent55

Only the - between the a and the root changes to +.

6. anonymous

Ok thanks @mathstudent55

7. mathstudent55

You're welcome. $$(a - \sqrt{a - 1})(a + \sqrt{a - 1})$$ follows the pattern $$(a - b)(a + b) = a^2 + b^2$$ The root term will disappear after multiplication. If you change the sign inside the root, it no longer follows the pattern of the product of a sum and a difference and the root terms will still be there after multiplication.

8. anonymous

Got it