Still need to know how to do these

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.

I’m still confused on how to work the percentages

The functions f(x) and g(x) are shown in the graph f(x)=x^2 what is g(x) ?