The length of a rectangle is 5 inches less than 3 times the width. the perimeter of the rectangle is 14 inches. find the length and width of the rectangle.
i did this: length 3x-5; width 3x then i did guess and check and came up with x=2 solving the problem with a perimeter of 14. but, the answer is supposed to be length 4inches, width 3inches.
explain what i did wrong. i know the answer but not how to get it.

Now max recorded the heights of 500 male humans. he found that the heights were normally distributed around a mean of 177 centimeters. which statements about max’s data must be true? a) the median of max’s data is 250 b) more than half of the data points max recorded were 177 centimeters. c) a data point chosen at random is as likely to be above the mean as it is to be below the mean. d) every height within three standard deviations of the mean is equally likely to be chosen if a data point is selected at random.

Math it's appreciated. (picture provided)

Combine like terms to make a simpler expression 3z+z