Question

The midpoint of XY is (3, -5), and point Y is located at (-1, –9). Find the y-coordinate of point X.

a) -7
b) -1
c) 7
d) 1

Answer 1

The y-coordinate for point X is -1, which is answer option b). This is found by using the midpoint formula and the known coordinates of midpoint M and endpoint Y.

Step-by-step explanation:

To find the y-coordinate of point X given the midpoint coordinates and one endpoint, we use the midpoint formula which states that the midpoint M(x,y) is calculated as M = ((x1+x2)/2, (y1+y2)/2). In this question, the midpoint M is (3, -5) and one endpoint Y is (-1, -9). Let's denote the coordinates for X as (x, y). Since we know the midpoint's x and y we can set up the following two equations:

(3) = (x - 1)/2

and

(-5) = (y - (-9))/2

Now, we solve for y:

-5 = (y + 9)/2


-10 = y + 9


-19 = y

The y-coordinate for point X is -1, which means option b) is the correct answer.