Simplify: sqrt (21) (sqrt(7) + sqrt(3))

Question

a) 7 sqrt (3) + 3 sqrt(7)
b) 7 sqrt(3) + sqrt (3)
c) sqrt (210)
d) sqrt (147) + sqrt (63)''.

a

Answer 1

√21√7 + √3
= √3√7√7 + √3
= 7√3+√3
= 8√3

the answer matching this is b)
but they should have simplified this.

Answer 2

thanks reiny