Question

Find the value of k which the point (1,-2)lies on the line x-2y+k=0

Answer 1

given line is x-2y+k=0
as the point (1,-2) lies on given line
it means the point should satisfy the line
substitute point in line
1-2(-2)+k=0
1+4+k=0
5+k=0
k= -5 is answer

Answer 2

HELLO MATE ☺
___________________________⭐⭐⭐
$x = 1 \\ y = - 2 \\ now \: x - 2y + k = 0 \\ 1 - 2( - 2) + k = 0 \\ 1 + 4 + k = 0 \\ 5 + k = 0 \\ k = - 5 \\ \\ so \: \: value \: of \: k \: is \: - 5$
____________________________⭐⭐⭐
HOPE IT HELPS U✌✌
^_^