If $f: R \rightarrow R$ is defined by $f(x)=\left\{\begin{array}{ccc} x+4 & \text { for } & x

If $f: R \rightarrow R$ is defined by $f(x)=\left\{\begin{array}{ccc} x+4 & \text { for } & x < -4 \\ 3 x+2 & \text { for } & -4 \leq x < 4 \\ x-4 & \text { for } & x \geq 4 \end{array}\right.$ then the correct matching of List I fromList-II is :




Solution

$\because \quad f(x)=\left\{\begin{array}{ccc}x+4, & \text { for } & x < -4 \\ 3 x+2, & \text { for } & -4 \leq x < 4 \\ x-4, & \text { for } & x \geq 4\end{array}\right.$ (A) $f(-5)+f(-4)=(-5+4)+(3(-4)+2)$ $=-1+(-12+2)$ $=-1-10=-11$ (B) $\quad f(|f(-8)|)=f(|-8+4|)$ $=f(4)=4-4=0$ (C) $\quad f(f(-7)+f(3))$ $=f(-7+4+9+2)$ $=f(8)=8-4=4$ (D) $f(f(f(f(0))))+1$ $=f(f(f(2)))+1$ $=f(f(6+2))+1$ $=f(f(8))+1$ $=f(8-4)+1=f(4)+1=4-4+1$ $=1$

Asked in: AP EAMCET 2006

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