rate fee=$29
charge per minute=$0.12
C(m)=function that represents the total monthly cost.
m=number of minutes spoken.
The equation would be:
C(m)=0.12m + 29
This is similar to the slope-intercept form of a line;
y=mx +b
m=slope
b=y-intercept
but we have written, C(x) instead of y; 0.12 instead of m, and 29 instead of b.
if m=50;
C(50)=0.12(50)+29=6+29=35
Answer: the equation would be: C(m)=0.12m+29; if we talk 50 minutes that month the cost would be $35.