describe a pair of real-world variables that could be related by a graph of this shape
问题描述：
describe a pair of real-world variables that could be related by a graph of this shape
我画了一个linear function
关键是怎样描述？能举个例子吗
答
变量来自于函数,函数与图形相符.
如：图形是一个圆,半径为r,则满足x²+y²=r²的变量(x,y)即可.
题目应该是让找出图形的函数表达式.他已经给了函数表达式：f(X)=2x+3那就任取一个x，如x=0，得到对应的f(x)=3(0，3)即可可能是要画出直线，然后在直线上标出一个点及其坐标