1.
Let f:RRf: \mathbb{R} \to \mathbb{R} be a function defined as
f(x)={5,x1a+bx,1<x<3b+5x,3x<530,x5f(x) = \begin{cases} 5, & x \le 1 \\ a + bx, & 1 < x < 3 \\ b + 5x, & 3 \le x < 5 \\ 30, & x \ge 5 \end{cases}
Then ff is: