tolong dijawab dengan cara kerjanya

y = mx + c, dimana m = garadien.
a) 4y = kx -12
y = (kx -12)/4
y = (k/4)x -3 ==> k/4 = 4, maka k = 4×4 = 16
b) 3x - ky -15 = 0
ky = 3x -15
y = (3x -15)/k
y = (3/k)x -15/k ==> 3/k = -3.
-3k = 3 ==> k = 3/-3 = -1
c) gradien garis melalui dua titik / m = ∆y/∆x.
titik (k , 4),(-1, -3)
m = (-3-4)/(-1-k) = -2
(-7)/(-1-k)/= -2
-2(-1-k) = -7
2 +k = -7
k = -7-2
k = -9
d) ( -2, k ) dan ( 5, 1)
m = (1-k)/(5 - -2) = 6
( 1 - k ) /(5+2) = 6
( 1 - k )/7 = 6
1 - k = 7×6
1 - k = 42
-k = 42 - 1
-k = 41
k = -41