Answer :
here rt(7) and -rt(7)will be cancelled and -1/rt(7) and +1/rt97) cancelled then 1 and -1 will be cancelled
then we get
a+brt(7)=0
a=-brt(7)
solving this we get
a=-rt(7)
b=1
then we get
a+brt(7)=0
a=-brt(7)
solving this we get
a=-rt(7)
b=1