TS EAMCET 04 May 2019 Shift 2 Solved Paper

Consider the figure shown below. Now
xy+4x−5y−20‌‌=0
(x−5)(y+4)‌‌=0‌‌‌‌‌⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅(I)
And
xy−5x+4y−20=0
(x+4)(y−5)=0‌‌‌‌‌⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅(II)
The equation of diagonal AC is,
y+4=x+4
x−y=0
The equation of diagonal BD is,
y+4=−x+5
x+y−1=0
Combined equation of diagonal are,
(x−y)(x+y−1)=0
x2−y2−x+y=0
Hence,
k=1
l=1
Therefore,
k+l‌‌=1+1
‌‌=2