设Y=aX+b,(X,Y)分别为以下几组数据:(0.265,3.835)(0.256,3.764)(0.9,12.578)(0.720,10.158)(0.894,12.106)(0.312,4.614)(0.449,6.599)(0.228,3.423)(0.271,4.087)(0.330,4.989)(0.314,4.753)(0.459,6.800)(0.473,6.979)(0.631,9.310),求a,b之间的函数关系式,需要列出详细解题步骤!!!