Answer:
3x + y = 9.5
Step-by-step explanation:
1) The equation of a line is in the form of y = mx + c, where m is the gradient and c is the y-intercept. Write the given values in that form.
y = -3x + c
2) Find the value of k by using the following formula: m = y2 - y1 / x2 - x1. We already know m.
-3 = 8 - k / k - 3
-3(k - 3) = 8 - k
-3k + 9 = 8 - k
-3k + k = 8 - 9
-2k = -1
k = -1/-2
k = 1/2
3) Therefore, a line with gradient of - 3 passes through the points (3, 1/2) and (1/2, 8). We can find the y-intercept (c). To do so, choose one of the coordinates and substitute.
y = -3x + c
1/2 = -3(3) + c
1/2 = -9 + c
1/2 + 9 = c
9.5 = c
Completed equation of the line: y = -3x + 9.5
4) Write it in the form of ax + by = c.
3x + y = 9.5
