Tolong bantu plisss, makasih :))

A. A ( -8 , a)
y = – 1/4x + 15
y =- 1/4 x (-8) + 15
= 2+15 =17
a = 17

b. B (b, 5)
4x – 3y + 7 = 0
4x – 3 x 5 + 7 = 0
4x – 15 + 7 = 0
4x -9 = 0
4x = 9
x = 2,25

b = 2,25

kalo ga salah gini