You would need to see the rest of the equation to plug in 7 for x. Treat it as y=equation and replace any x with 7.
About 68% of the people will score between 85 and 115.
The values of 85 and 115 are exactly 15 points away, or 1 standard deviation, away from the mean.
According to the empirical rule, about 68% of the values in a normal distribution are within 1 standard deviation of the mean.
Y=1/3x+2
(-6,0)
(0,2)
(6,4)
