## anonymous one year ago Help with radicals

1. anonymous

|dw:1434336375394:dw|

2. anonymous

@peachpi @LeibyStrauss

3. anonymous

do you know what the conjugate is?

4. anonymous

@peachpi Idk what that is

5. anonymous

can you explain

6. anonymous

the conjugate is where you change the sign of the radical in the denominator and multiply by it to get rid of the square root in the denominator. Your denominator is 9-√5, so the conjugate is 9+√5. So to solve your problem you need to simplify this |dw:1434336787389:dw|

7. anonymous

@peachpi ok than what would be next?

8. anonymous

|dw:1434337068377:dw|

9. anonymous

the top is right. FOIL the bottom

10. UsukiDoll

the first part of the denominator is right... second part... no because when we are multiply square roots it's just that number

11. UsukiDoll

for example $(\sqrt{3})(\sqrt{3}) = 3$ now apply that example to your problem

12. anonymous

@UsukiDoll I'm lost so how would the denominator look?

13. UsukiDoll

$(9-\sqrt{5})(9+\sqrt{5})$ is your denominator .. use foil.. the O and I cancels out

14. anonymous

so it would be 81+5?

15. anonymous

yes

16. UsukiDoll