Chapter 7 - Exponents and Exponential Functions - 7-1 Zero and Negative Exponents - Mixed Review - Page 419: 81

$y=-x+4$

The slope-intercept form of a linear equation of a non vertical line is $y=mx+b$, where $m$ is the slope and $b$ is the $y$-intercept. We plug in the given values of $m$ and $b$: $y=-1\times x+4$ We simplify: $y=-x+4$