Question

please give answer the question

Answer 1

ABC similar to STC by AA test ( angle C is common, angle B = angle T).
therefore AB/ST = BC/TC
therefore, p/x = (q+r)/r
p×r = x(q+r)
x = pr/(q+r)

Answer 2

By using Basic Proportionality theorem, $\frac{r}{r+q}= \frac{x}{p}$
Which implies that,$x= \frac{rp}{r+q}$

So, it is expressed in terms of 'r', 'p' and 'q'.