Question

a student is measuring the length of an icicle, $y$, every hour, $x$. the icicle is currently 9 inches long and is melting at a rate of 0.6 inches per hour. find and interpret the slope for this relationship.
$\bigcirc$ 9; the length of the icicle when the student first measures it
$\bigcirc$ -9; the length of the icicle when the student first measures it
$\bigcirc$ 0.6; for every additional hour, the length of the icicle increases by 0.6 inches
$\bigcirc$ -0.6; for every additional hour, the length of the icicle decreases by 0.6 inches

Explanation:

Step1: Identify linear model form

The relationship follows $y = mx + b$, where $m$ = slope, $b$ = initial length.

Step2: Define slope meaning

Slope is the rate of change of $y$ (length) per $x$ (hour). Since the icicle melts (decreases) at 0.6 inches/hour, $m=-0.6$.

Answer:

-0.6; for every additional hour, the length of the icicle decreases by 0.6 inches