Sorry I'm probably too late since Quizziz doesn't wait unless you have the freeze timer thing.
y = mx+b
b is the y intercept. The y intercept (when x=0) is given in the table.
Now plug a coordinate in to solve for m.
My coordinates: (1,5)
5 = m + 3
Solve.
2 = m
m = 2
Note: never plug in the y intercept when looking for m.
You can also find the slope by (subtracting the y value of one coordinate from another y value of another coordinate)/(subtracting x value from the first y coordinate above from the x value from the second coordinate).