A(4,h) B(h+3,7) Kemiringan -1/4. Berapa nilai h?

Bab Persamaan Garis
Matematika SMP Kelas VIII

m = gradien = kemiringan

m = -1/4
(y2 - y1)/(x2 - x1) = -1/4
(7 - h)/(h + 3 - 4) = -1/4
4 (7 - h) = (-1) (h - 1)
28 - 4h = -h + 1
28 - 1 = 4h - h
27 = 3h
h = 9