Right because if you make a triangle like that than you make a right a right angle
(2 − 3i) + (x + yi) = 6
We add the left hand side
(2+x) + (-3+y)i = 6
6 can be written in a+ib
6 can be written as 6 + 0i
(2+x) + (-3+y)i = 6 +0i
Now we frame 2 equations
2 + x= 6
-3 + y =0
Solve the first equation
2 + x = 6
Subtract 2 from both sides
x = 4
solve the second equation
-3 + y =0
Add 3 on both sides
y= 3
So x+yi is 4+3i
