## miah 2 years ago Help ?

1. miah

2. miah

@SandeepReddy

3. SandeepReddy

what is (a+b)*(c+d) ?

4. miah

uhm ?

5. SandeepReddy

what is the result of ( a+b)*(c+d) ?

|dw:1363810206819:dw|

7. miah

something with a fraction

8. SandeepReddy

\[a*(b+c) = a*b+a*c \]

9. SandeepReddy

10. miah

11. SandeepReddy

In the same way \[(a+b)*(c+d) = a*(c+d)+b*(c+d)\]

12. SandeepReddy

that is a*c+a*d+b*c+b*d

So be it.......

14. SandeepReddy

now for help1, help2 and help4 you can use above formulae that i hav given

15. miah

but Idk how to do it

16. SandeepReddy

|dw:1363810963051:dw||dw:1363811076093:dw|

17. SandeepReddy

GOt it ?@miah

18. miah

yes, kind of. I was going to chose that answer. so the second one ?

@SandeepReddy Good Explanation....... And I see I wasn't wrong ;) FOIL METHOD?

20. miah

sorry :P can you help with the second one ?

21. SandeepReddy

22. SandeepReddy

Do it yourself @miah now u know how to do these kind of problem , give it a try! you can do it , its simple than we think!

23. miah

I still dont know how to do it

24. SandeepReddy

Remember \[(a+b)(a-b) = a^2 -b^2\]

25. SandeepReddy

Its very important as important as \[(a+b)^2 = a^2+2ab+b^2\]

26. SandeepReddy

|dw:1363812124287:dw|

27. miah

I got it right!

28. SandeepReddy

as for as rationalizing problem is concerned, multiply numerator and denominator with root 2

29. SandeepReddy

Now one problem left, can u do it urself?

30. miah

wait,.. no i didnt ?

31. miah

what answer choice is that ?

32. miah

wait. i did get it right (:

33. miah

I need help with the third one :o

34. miah

3√2/2

35. SandeepReddy

yes correct!