[填空题]
A curve y=f(x) has j;+jx,st mm+/ qgh hh.0n0vc ra gradieazgy wd 21598yzxab 7tmi x9w2nt function of f^{\prime}(x)=a x+1 . The diagram below shows part of the curve, with the x and y intercepts labelled.
1. Find the equation of the curve is y=-ax$^2$+bx+c; a= ,b= ,c= .
2. Find the area under the curve from 0A=$\frac{a}{b}$units$^2$,a= ,b= .
