Final answer:
The equation of a line in slope-intercept form is y = mx + b, where m is the slope and b is the y-intercept.
Step-by-step explanation:
The equation of a line in fully simplified slope-intercept form is given by y = mx + b, where m represents the slope and b represents the y-intercept. The slope defines the steepness of the line, generally calculated as the rise over the run. The y-intercept is the value of y where the line crosses the y-axis. Therefore, the correct equation in slope-intercept form is A) y = mx + b.