Question

Question no 5 please solve fast.

Answer 1

Answer:

ABllCDllPQ

ABllPQ

now, in triangle ABD similarPQD

PQ/AB=QD/BD .......... 1

similarly BCD similar BQD

PQ/CD =BQ/BD.......2

by adding eq. 1&2

PQ/AB+PQ/CD=BQ+QD/BD

PQ(1/x+1/y) =1

z(1/x+1/y) =1

1/x+1/y=1/z

proved