Chapter 2 Linear Equations and Functions - 2.7 Use Absolute Value Functions and Transformations - 2.7 Exercises - Problem Solving - Page 129: 39

$y=-\frac{140}{69}|x-69|+140$.

The absolute value functions have the form $y=a|x-b|+c$ where $(b,c)$ is the vertex of the function. Hence here because the vertex is at $(69,140)$, $y=a|x-69|+140$. Since $(0,0)$ is on the function, plugging in the values we get: $0=a|0-69|+140\\-140=69a\\a=-\frac{140}{69}$. Thus $y=-\frac{140}{69}|x-69|+140$.