Question

A Sand dune stands 5 feet above sea level. the hill is eroding at a rate of 1 foot per 20 years. let y represent the height of the sand dune after x years. which equation represents the situation

Answer 1

5 - (1 + 20) = yx

Explanation:

So if 5ft is the original height, we would need to distribute that to decrease in the following years. That is where the 5 - comes from. Next we know that is it is eroding 1 foot in 20 years so that is 5- (1+20) You HAVE to distribute that and not add. Then it equals y the height of the dune in x, the years. Honestly 5 feet above sea level is kinda puny for a sand dune ;P.