[填空题]
A curve y=f(x) has a gra6(jyz )osarhncn4cd5y el( wa96 +h i9dient f;a vocaro: u;b.r9 d*hunction of $f^{\prime}(x)=a x+5 $. The diagram below shows part of the curve, with the x and y intercepts labelled.
1. Find the equation of the curve,y=$-ax^2+bx+c$;a= ,b= ,c= .
2. Find the area under the curve from 0 ,b= .