Surd Help

Just working through the P1 thing, and I'm stuck on this excerise.
NOTE: For the below # is the square root /surd sign.
These are all RATIONALISING THE DENOMINATOR.

PROBLEM A
1 / #3 - 1
I changed this and ended up with
1 (-1 - #3) / -1 + #3 (-1 - #3)
Which i then worked to get
-1 - #3 / - 2
Is there anything else to do?

PROBLEM B
#43 - #23 / #43 + #23
What???????

(√43 - √23)(√43 - √23)
How you do that?
Whats √43 x - √23??

whats command for the sqrt sign ? alt + some numbers ?

thats so tedious D:

thats easy now but what if it aint there, oh well ill just use sqrt(x)