Question

Please solve question 21
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Its urgent

Answer 1

(2) a<0, b<0

As

√a √b = √ab

if a<0, b<0

√-1 √|a| √-1 √|b|

√ab (√-1 √-1)

√ab( -1)

-√ab which is not equal to √ab

Hence (2)

Answer 2

hey mate

here is the answer....

Answer:

let us prove this by the counter-example method

√3*√7=√21

so,the identity is true when a>0 and b>0.

√-3*√-7=-√21

=>√-1√3*√-1*√7=(√-1)²√21

=>-√21

so, this is not true when a<0 and b<0.