Which of the following represents an equation of a line that passes through 2,9 and 1,4

(2,9)(1,4)
slope = (4 - 9) / (1 - 2) = -5/-1 = 5

y = mx + b
slope(m) = 5
use either of ur points...(1,4)...x = 1 and y = 4
now we sub and find b, the y int
4 = 5(1) + b
4 = 5 + b
4 - 5 = b
-1 = b

so ur equation is : y = 5x - 1or  5x - y = 1