Question

Given that points (-1, -9) and (7, r) lie on a line with a slope of 5/4, find the missing coordinate r.

A) 11
B) 12
C) 13
D) 14

Answer 1

To find the missing coordinate r, we can use the slope formula and solve for r.

Step-by-step explanation:

To find the missing coordinate, we can use the slope formula: slope = (y2 - y1) / (x2 - x1).

Let's assign the coordinates (-1, -9) to (x1, y1) and (7, r) to (x2, y2). We can plug in the values and solve for r:

(5/4) = (r - (-9)) / (7 - (-1))

Multiplying both sides of the equation by (7 - (-1)) yields:

5/4 = (r + 9) / 8

Multiplying both sides of the equation by 8 gives:

10 = r + 9

Subtracting 9 from both sides of the equation gives:

1 = r

Therefore, the missing coordinate r is 1. So, the correct answer is A) 11.