Final answer:
The gradient of the line is 3, and the y-intercept is 9, resulting in the linear equation y = 3x + 9.
Step-by-step explanation:
The question is asking us to work out the gradient and the y-intercept of a given line on a graph.
Based on Figure A1 provided in the description, we can identify that the y-intercept of the line is 9, as this is the point where the line crosses the y-axis. Furthermore, the slope, or gradient, of the line is given as 3. This means for every 1 unit increase in the x-direction (horizontal axis), the y-value (vertical axis) rises by 3 units.
The equation of a line in slope-intercept form is y = mx + b, where m is the slope and b is the y-intercept. Therefore, the equation for this line, based on the provided information, would be y = 3x + 9.