·紧急求助!一个matlab编程问题

有公式:y=a(exp(bx)),已知x=4,6,8,12,20,26,36,56,95,240,360,541,2147,12000;对应的y=0.25,0.22,0.2 ,0.18,0.16,0.14,0.12,0.1,0.08,0.06,0.04,0.02,0,0.现要用matlab求a,b要具体的matlab程序.并画图
本人急用此程序,希望matlab高手指教,万分感谢!!!