A cell phone plan charges $39.95 a month plus 15 cents per text message sent and 15 cents per text message received. Using s to represent the number of text messages sent in one month and r to represent the number of text messages received in one month, the following equation can be used to calculate the total monthly cost, c: c = 39.95 + 0.15(s + r)

If it is known that the total monthly cost is $53.45 and 63 text messages were received, solve for s, the total number of text messages sent.

c= 39.95 +0.15 (s + r) (take the 63 received and plug it in for r and 53.45 in for c then solve)

53.45= 39.95 +0.15 (s +63) (use the distributive property)

53.45 = 39.95 + 0.15s + 9.45 (combine like terms on the right side)

53.45 = 49.40 +0.15s (subtract 49.40 from both sides)

4.05 = 0.15s (divide both sides by 0.15 so isolate s)

s= 27 (how many text messages were sent)

Step-by-step explanation:

I hope this helps :)

irrational, then, just means all the numbers that aren't rational. every integer is a rational number, since each integer n can be written in the form n/1. however, numbers like 1/2, 45454737/2424242, and -3/7 are also rational, since they are fractions whose numerator and denominator are integers.

step-by-step explanation: