f(x) = 3x + 1.....this is the same as y = 3x + 1.
In y = mx + b form, which is what y = 3x + 1 is in, the rate of change (slope) is in the m position and the y int (the initial value) is in the b position.
y = mx + b
y = 3x + 1
ur rate of change (slope)...number in the m position = 3
ur initial value (y int)...number in the b position = 1
so rate of change = 3 and initial value = 1