If the lines $x+y+\mu =0$  and $\lambda x-5y-5=0$  are identical, then $\lambda +\mu =$

If the line is identical the it co – efficient are equal

$\mu =1,\lambda =-5$

$\lambda +\mu =1-5=-4$

(or)

If the line is identical then condition

$\frac{a_1}{a_2}=\frac{b_1}{b_2}=\frac{c_1}{c_2}$

$\frac{1}{\lambda }=\frac{1}{-5}=\frac{\mu }{-5}$

$\lambda =-5,\mu =1$

$\lambda +\mu =-5+1=-4$