Use the table to write and solve an equation to tell you the number of minutes for which the cost of both phone companies is equal

Company A : 0.36 + 0.03m
company B : 0.06m

to find out when they are equal, set them equal to each other and solve for m, the number of minutes

0.36 + 0.03m = 0.06m
0.36 = 0.06m - 0.03m
0.36 = 0.03m
0.36 / 0.03 = m
12 minutes <=== they will be the same at 12 minutes

check...
company A : 0.36 + 0.03(12) = 0.72
company B : 0.06(12) = 0.72
correct

Cdoes not have two variables