The price y is a function of x, the speed of the processor.
In function notation this means, y=f(x), where f(x)=<span>101x + 207.85. </span> For example to calculate the (approximate) price of a laptop with processor 4 gigahertz, we let x=4, and plug in f.
That is the price y for x=4 is calculated by y=f(4).
So, since y=f(x)=<span>101x + 207.85, the (expected) price of a laptop with processor speed 2.5 gigahertz is :
