Answer:
[tex]c=35r+10[/tex]
Step-by-step explanation:
We need to create a linear equation in the form: c = mr + b
(where m is the slope and b is the y-intercept)
Choose two ordered pairs from the table: (2, 80) and (4, 150)
Let [tex](r_1,c_1)[/tex] = (2, 80)
Let [tex](r_2,c_2)[/tex] = (4, 150)
Calculate the rate of change (slope of linear equation) by dividing the change in c by the change in r:
[tex]\textsf{slope} \ m=\dfrac{c_2-c_1}{r_2-r_1}=\dfrac{150-80}{4-2}=35[/tex]
Now use point-slope form of linear equation to create final equation:
[tex]c-c_1=m(r-r_1)[/tex]
[tex]\implies c-80=35(r-2)[/tex]
[tex]\implies c=35r+10[/tex]
