[填空题]
A curve y=f(x) has a ilt/ lf 4u5xoy(9rfi8gradient funcl +s( sxja(-drtion 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= .
