Answer:
x+1 , x<-1
x²-bx-4 , -1≤x≤4
1/2 x +a
substitute x=-1 , continuous everywhere
x+1=x²-bx-4 when x=-1
-1+1=-1²-b-4
then for :
x²-bx-4=1/2 x +a for x=4
4²-4b-4=1/2x+a
16-4(3)-4=4/2+a
16-12-4-2=a
the equations will be :
x+1
x²-3x-4
1/2x-2
I hope this help