Answer:
y=3x+15
Explanation:
pick any two points (ill pick (1, 18) and (2,21))
to find the slope, use the slope formula: (21-18)/(2-1) = 3
you didnt specify which form you want the equation to be, so for slope intercept form, it is y = 3x + b, and b is the y intercept which we know is 15 (0, 15). y = 3x+15