The graph models the value of an automobile over a 7 year period of time. Which equation best represents the relationship between x, the age of the automobile in years, and y, the value of the automobile in dollars

Find x to the nearest hundredth place

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

Don't know how to find x given these segment lengths