Answer
See graph below.
The equilibrium price is about ${{\$}} 3.50$
.
Work Step by Step
Treat p as an independent variable (on the horizontal, "x-axis") and q as the dependent variable (on the vertical, "y- axis").
Using your graphing device, enter the formulas
Demand:$\quad y=64*x^{\wedge}(-0.76)$
Supply:$\quad y=2.5*x+15.5$
Set viewing window to $[0,15]\times[0,35],$ or similar.
(See attached screenshot.)
The intersection point is at approximately $(3.56,24.40)$,
so the price $p$ when demand=supply (the equilibrium price) is about
${{\$}} 3.50$
