Final answer:
The equation of the straight line is y = 3x + 9, where the slope (m) is 3 and the y-intercept (c) is 9.
Step-by-step explanation:
To work out the equation of the straight line in the form y = mx + c, where m is the slope and c is the y-intercept, we can use the given details from Figure A1. According to the information provided, the slope (m) of the line is 3.
This means for every increase of 1 on the horizontal axis (x), there is a rise of 3 on the vertical axis (y). The y-intercept (c), which is the point where the line intersects the y-axis, is given as 9. Therefore, substituting these values into the equation, we get y = 3x + 9.