Answer:
y=.1x+40; Your total monthly bill is $48 for 80 text messages.
Step-by-step explanation:
y is your total bill
x represents each text message
40 is you cellphone bill cost
.1 is the cost per text message
(y=.1x+40 becomes your equation)
plug 80 to represent "x"
y=.1*80+40 ---> y=48
your total monthly bill is $48
