Step-by-step explanation:
average rate of change of function is given by :
[tex]f= (f(a+h)-f(a))/h[/tex]
where
[tex]f(x)=3x[/tex]
and a= 7
so inserting values is formula for h=1
[tex]f=(f(7+1)-f(7))/1[/tex]
[tex]f= f(8)-f(7)= 3(8)-3(7)=24-21=3[/tex]
now for h= 0.1
[tex]f=(f(7+0.1)-f(7))/0.1=(f(7.1)-f(7))/0.1=(3(7.1)-3(7))/0.1[/tex]
[tex]f=3[/tex]
similarly average rate of change of given function is same for all given step sizes.