Add the following complex numbers: (3-9i) + (6-21i)
A. 9-7i
B. 9-11i
c. -3-71
D. -3-11i

i am unable to solve this problem

step-by-step explanation:

for this case we have by definition, if two lines are perpendicular, then the product of their slopes is -1.

then, given the following line:

so,

we are looking for m_ {2}:

then, the line is given by:

we find "b" replacing the given point:

finally, the equation is:

option c