for a constant rate of change
find the rate of change for table 1
[tex]r=\frac{15-12}{2-1}=\frac{3}{1}=3[/tex][tex]r=\frac{18-15}{3-2}=\frac{3}{1}=3[/tex]
so table 1 has a constant rate of change.
for table 2
[tex]r=\frac{21-20}{2-1}=1[/tex]
[tex]r=\frac{23-21}{3-2}=2[/tex]
so table 2 has a variable rate of change.
for table 3
[tex]r=\frac{7-5}{2-1}=2[/tex]
[tex]r=\frac{9-7}{3-2}=2[/tex]
so table 3 has a constant rate of change.
so the correct answer is option A
