Q.

If a and b are roots of x2-px+q=0, then 1a+1b=

1 1p  
2 1q  
3 12p  
4 pq  

Ans.

(4)

Given a,b are roots of x2-px+q=0

∴  Sum, a+b=p, product, ab=q

        pq=sum of rootsproduct of roots=a+bab=1a+1b

∴  pq=1a+1b