Final answer:
The equation of the straight line KL is y = 3x + 9, with a slope of 3 and a y-intercept of 9. The x-intercept of line KL is -3.
Step-by-step explanation:
To write the equation of the straight line KL, we need to identify the slope (m) and the y-intercept (b). According to the information given, for a linear equation in the form y = mx + b, m represents the slope, and b represents the y-intercept. If we reference Figure A1, we see an example of a straight line with a y-intercept of 9 and a slope of 3. Therefore, the equation of line KL can be written as y = 3x + 9.
The x-intercept of a line is found when y=0. Plugging 0 into the equation for y, we have 0 = 3x + 9. Solving for x, we subtract 9 from both sides to get -9 = 3x, and then divide both sides by 3 to find x = -3. Therefore, the x-intercept of line KL is -3.