8．已知函数f(x)={(52)x−1,x⩽24−x,x>2f(x)=\left\{\begin{array}{l}{(\frac{5}{2})^{x}-1,x\leqslant 2}\\ {4-x,x>2}\end{array}\right.f(x)={(25)x−1,x⩽24−x,x>2，则函数g(x)=f(x)−xg(x)=f(x)-\sqrt{x}g(x)=f(x)−x的零点个数为((( )))