The length of a text message is conversation is normally distributed with a mean of 2 min and a standard deviation of 0.5 min.
what is the probability that a conversation last longer than 3 min ?

assuming you mean addition: addition and subtraction are reverse operations.

step-by-step explanation:

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10