9) f(8) for f(x) = f(x)= ) 8x+1,&ifxlt 1 8x,&if8leqslant xleqslant 13 8-3x,&ifxgt 13 A) 40 B) -16 C) 9 D) 64

To find $f(8)$, we need to determine which piece of the piecewise function applies when $x = 8$.<br /><br />Given the function:<br />\[ f(x) = \begin{cases} <br />8x + 1, & \text{if } x < 1 \\<br />8x, & \text{if } 8 \leq x \leq 13 \\<br />8 - 3x, & \text{if } x > 13 <br />\end{cases} \]<br /><br />Since $8$ falls within the range $8 \leq x \leq 13$, we use the second piece of the function, which is $8x$.<br /><br />Now, substitute $x = 8$ into the function:<br />\[ f(8) = 8 \times 8 = 64 \]<br /><br />Therefore, the correct answer is:<br />D) 64