In the equation of a line in slope-intercept form \( y = mx + b \), \( m \) represents the slope and \( b \) represents the y-intercept.
For the equation \( y = -3x + 8 \):
- The slope \( m \) is \(-3\).
- The y-intercept \( b \) is \( 8 \).
Thus, the slope is \(-3\) and the y-intercept is \( 8 \).