Limits Continuity And Differentiability

If the function \(f(x)\), defined below, is continuous on the interval \([0,8]\), then $$f(x)=\left\{\begin{array}{cc}x^2+a x+b & , \quad 0 \leq x < 2 \\ 3 x+2, & 2 \leq x \leq 4 \\ 2 a x+5 b & , 4 < x \leq 8\end{array}\right.$$