Suppose $f$ is a linear function with $f ( 7 ) = 25.13$ . If the slope of $f$ is 2.59, what value of $x$ gives $f ( x ) = 12$ ?
A) $x =$38.95
B) $x =$1.93
C) $x =$38.08
D) $x =$2.42

Question

Suppose $f$ is a linear function with $f ( 7 ) = 25.13$ . If the slope of $f$ is 2.59, what value of $x$ gives $f ( x ) = 12$ ?
A) $x =$38.95
B) $x =$1.93  
C) $x =$38.08 
D) $x =$2.42

Quizplus · Accepted Answer

Given $f(x) = mx + b$, where $m$ is the slope and $b$ is the y-intercept. We know $f(7) = 25.13$ and the slope $m = 2.59$. To find $b$, use $25.13 = 2.59(7) + b$. Solving for $b$, we get $b = 25.13 - 2.59(7)$. To find $x$ when $f(x) = 12$, set up $12 = 2.59x + b$ and solve for $x$, which gives $x = 1.93$.

Suppose fff Is a Linear Function With f(7)=25.13f ( 7 ) = 25.13f(7)=25.13

Suppose $f$ Is a Linear Function With $f ( 7 ) = 25.13$