$$\text { Let } f ( x ) = 14 x + 8 \text {. Then simplify the expression } \frac { f ( x ) - f ( 9 ) } { x - 9 } \text {. }$$
A) 15
B) 14
C) 19
D) 11
E) undefined

Question

$$\text { Let } f ( x ) = 14 x + 8 \text {. Then simplify the expression } \frac { f ( x ) - f ( 9 ) } { x - 9 } \text {. }$$ 
A) 15
B) 14
C) 19
D) 11
E) undefined

Quizplus · Accepted Answer

The expression simplifies to the slope of the line represented by the function $f(x) = 14x + 8$. Substituting $f(x)$ and $f(9)$ into the given expression, we get $\frac{14x + 8 - (14\cdot9 + 8)}{x - 9}$. Simplifying the numerator, we find that the $+8$ and $-8$ cancel out, and we're left with $14x - 14\cdot9$, which simplifies further to $14(x - 9)$. Dividing this by $x - 9$ gives us $14$, indicating that the slope of the line, and thus the value of the expression, is $14$.

Let f(x)=14x+8. Then simplify the expression f(x)−f(9)x−9. \text { Let } f ( x ) = 14 x + 8 \text {. Then simplify the expression } \frac { f ( x ) - f ( 9 ) } { x - 9 } \text {. } Let f(x)=14x+8. Then simplify the expression x−9f(x)−f(9)​.

$\text { Let } f ( x ) = 14 x + 8 \text {. Then simplify the expression } \frac { f ( x ) - f ( 9 ) } { x - 9 } \text {. }$