Solve this question

Solve this question and O lic in quadranL I hen tind the value sine

is the answer 17?
i am just askin if its right then i will post the solution

tanA=7/24 ==>sinA=-7/25 cosA=-24/25 sinA - cosA = -7/25 +24/25 =17/25

ohh  wait sorry for the wrong answer.
so, okay
tan theta = perp/base
now put it in the triangle 
you get hyp. = 25.
now find the sin theta and cos theta from the triangle
i.e.
sin theta = 7/25 
and 
cos theta = 24/25.
plus,
it is mentioned that theta is present in third quad.
there sin and cos func. are negative.
therefore the eqn. will change to,
cos theta - sin theta (since -(-cos theta) =  cos theta).
now put the values of cos theta and sin theta in the eqn.
we get,
24/25-7/25 = 17/25.
and i hope that is the required answer.
Hope it helps!