设y=a(x＋2)²＋4,以(1,5)代入,得：5=9a＋4,得：a=1/9,则：y=(1/9)(x＋2)²＋4=(1/9)x²＋(4/9)x＋(40/9),则：a=(1/9),b=(4/9),c=40/9