Points (-21, 5) and (-7, y) have a slope of -1/7. Find the y coordinate of the point.
The formula for the slope between two points, (x1, y1) and (x2, y2), is given by:
slope = (y2 - y1) / (x2 - x1)
Given that the slope is -1/7, we can write the equation as:
-1/7 = (y - 5) / (-7 - (-21))
Simplifying the denominator, we have:
-1/7 = (y - 5) / 14
Cross multiplying, we get:
-14 = 7(y - 5)
Expanding the right side of the equation, we have:
-14 = 7y - 35
Adding 35 to both sides of the equation, we get:
21 = 7y
Dividing both sides by 7, we get:
y = 3
Therefore, the y-coordinate of the point (-7, y) is 3.