The graph of function 1 represents a horizontal line, for this type of line their slope (rate of change) is always zero.
Function two represents also a line, this equation is in the slope-intercept form:
y=mx+b, where m is the slope and b the intercept since the rate of change of this line is the value of the slope, which is 7, then:
rate of change of function 1=0
rate of change of function 2=7
To know how much more is the rate of change of function 2 that function 1, we just have to subtract the the rate of change of the first function from the second one:
7-0=7
Then, the rate of cha