To write the equation of a line in slope-intercept form, which is y = mx + b, we need to find the slope (m) and the y-intercept (b) of the line passing through the given points (3, 1) and (2, 5).
Step 1: Calculate the slope (m).
The formula for the slope (m) between two points (x1, y1) and (x2, y2) is:
m = (y2 – y1) / (x2 – x1)
In our case, let (x1, y1) = (3, 1) and (x2, y2) = (2, 5).
So, we can plug in these coordinates:
m = (5 – 1) / (2 – 3) = 4 / -1 = -4
Step 2: Use slope and one point to find y-intercept (b).
We can now use the slope and one of the points to find the y-intercept (b). Let’s use the point (3, 1). We substitute the slope (m) and the coordinates of the point into the slope-intercept form:
y = mx + b
1 = -4(3) + b
1 = -12 + b
Now, solve for b:
b = 1 + 12 = 13
Step 3: Write the equation in slope-intercept form.
Now that we have both m and b, we can write the equation:
y = -4x + 13
This is the equation of the line in slope-intercept form that goes through the points (3, 1) and (2, 5).