Final answer:
The equation of the line with slope -8 and y-intercept 9 in slope-intercept form is y = -8x + 9.
Step-by-step explanation:
To write an equation in slope-intercept form for the line with a given slope and y-intercept, you use the formula y = mx + b, where m is the slope and b is the y-intercept. In this case, we were told the slope (m) is -8 and the y-intercept (b) is 9. Therefore, the equation of the line in slope-intercept form is:
y = -8x + 9
This equation tells us that for every unit increase in x, the value of y decreases by 8 units, starting at the point where y is 9 when x is 0.