Question

gradient of a straight line through the points (4,6) and (16,54)

Answer 1

$m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{54 - 6}{16 - 4} = \frac{48}{12} = 4$

$y - y_1 = m(x - x_1) \\ y - 6 = 4(x - 4) \\ y - 6 = 4(x) - 4(4) \\ y - 6 = 4x - 16 \\ y = 4x - 10$