To find the equation of a line that passes through two points, we can use the slope-intercept form of the equation of a line, which is given by:
y = mx + b
Where:
- m is the slope of the line
- b is the y-intercept of the line
First, we need to calculate the slope (m) using the coordinates of the two given points: (0, 9) and (3, 0). The formula for calculating the slope between two points (x1, y1) and (x2, y2) is:
m = (y2 – y1) / (x2 – x1)
Substituting the coordinates:
m = (0 – 9) / (3 – 0) = -9 / 3 = -3
Now that we have the slope, we can substitute one of the points into the slope-intercept form to find the y-intercept (b). Let’s use the point (0, 9):
9 = -3(0) + b
This simplifies to:
b = 9
Now we have both components of our equation:
- Slope (m) = -3
- y-intercept (b) = 9
Thus, we can write the equation of the line:
y = -3x + 9
To summarize, the equation of the line that passes through the points (0, 9) and (3, 0) is:
y = -3x + 9