Chapter 2 - Linear and Quadratic Functions - Section 2.2 Building Linear Models from Data - 2.2 Assess Your Understanding - Page 133: 4

$\text{decrease}$; $0.008$

Consider the given line $y=-0.008x+14$ This line is of the form, $y=mx+c$, where $m$ is the slope. Here the slope is $-0.008$, which is negative. Hence, as $x$ increases by $1$ unit, the interest decreases by $0.008$.