Question

if 3+2 root 2=a+b root 2 then b=

Answer 1

compare both equation we get
a=3 b=2
: . b =2
compare means on both sides the nos. are in order. So we can equalize it.

a + brt(2)
= ...=..
3 + 2rt(2)

so a=3
and b=2.

Answer 2

Your Question :

$if \: 3 + 2\sqrt{2} = a + b \sqrt{2} \: \: then \: b = ....$
Your Answer :

Both are in the same form [ X + Y√p ]

So in LHS

X = 3

Y = 2

√p = √2

In RHS

X = a

Y = b

√p = 2

As √p is same in both LHS and RHS , it's coefficient must be equal

i.e b√2 = 2√2

b = 2

Also a = 3