math’s problem

题目

math’s problem
The number of records sold at a local music
store between 1970 and 1990 can be approximated by
y = −327t + 7000 ,
where y represents the number of records and
t represents the year with t = 0 corresponding
to 1970.
According to the model,in what year were
there 1650 records?

答案

注意到 approximate 是求近似值 我们把y=1650带入方程 解得x约等于16（如果是保留整数的话 若不是其实是16.491538...）由题应为 t=0代表1970 所以1970+16=1986 符合范围 原题大意 是给定你一个方程（含时间和记录...