Question

Which expression is equal to 228−−√−563−−√ ?

please help???

Answer 1

`-11√(7)`

Explanation:

Given expression,

`2√(28)-5√(63)`

`=2√(7* 4)-5√(7* 9)` ( HCF(28, 63) = 7 )

`=2√(7)* √(4)-5√(7)* √(9)`

`(\because √(a* b)=√(a)* √(b))`

`=2√(7)* 2-5√(7)* 3`

`=4√(7) - 15√(7)`

`=(4-15)√(7)` (By taking √7 common from both terms)

`=-11√(7)`