Question

You start at (1, 8). You move down 3 units. Where do you end?

Answer 1

(1,5)

Explanation:

x = 1

y = 8

If you move down 3 units, it means the y would be lower. This is because y is the vertical value in a pair of coordinates.

8-3 = 5

Answer 2

(1, 5)

Explanation:

Cartesian Coordinate and Transformation

A coordinate defined as point (x, y) is called Cartesian Coordinate. The x-coordinate represents right-left direction while the y-coordinate represents up-down direction.

Its transformation depends on how would you move the coordinate point. An example is if you start with (x, y) point and move to right 3 units, our new position will be at (x + 3, y).

Properties

Suppose we have point (x, y), if we move to right “a” units then the new point will be (x + a, y)

If we move (x, y) to left “a” units, our new point will be (x - a, y)

If we shift (x, y) up “a units”, you’ll get (x, y + a)

If we shift (x, y) down “a units”, we’ll have (x, y - a)

Solution

Suppose you start at (1, 8) and you move down 3 units, you can apply the transformation property to find your new position.

Since you move down, this means you are dealing with y-coordinate only so you’ll apply property of (x, y - a)

You’ll have (1, 8 - 3) which equals to (1, 5).

Hence, you’ll end at (1, 5).

Please let me know if you have any questions!