Final answer:
The fully simplified slope-intercept form of the given line, which has a slope of 3 and a y-intercept of 9, is y = 3x + 9.
Step-by-step explanation:
To write the equation of the line in slope-intercept form using the given information from Figure A1 Slope and the Algebra of Straight Lines, we will use the formula y = mx + b, where m represents the slope and b represents the y-intercept. Given that the slope (rise over run) is 3 and the y-intercept is 9, we can substitute these values into the formula to get the equation of the line.
The fully simplified slope-intercept form of the given line is therefore y = 3x + 9.