How to get coordinates to 2x+y=4 for -2 -1 0 1 2?

2 Answers

Oddman Profile
Oddman answered
If the values listed are those for x and you need to find y, you can solve for y as
  2x + y = 4
  y = 4 - 2x    (subtract 2x)
Your first x value is -2, so y is
  y = 4 - 2*(-2)    (put -2 where x is in the equation)
  y = 4 + 4 = 8
The first pair of coordinates is (x, y) = (-2, 8).

We can do the remaining x values in a list to save a little bit of effort and writing
  y = 4 - 2*{-1, 0, 1, 2}
  y = 4 - {-2, 0, 2, 4}
  y = {6, 4, 2, 0}

The remaining coordinate pairs are
  (-1, 6), (0, 4), (1, 2), (2, 0)
The Dragon Profile
The Dragon answered
There's a shorter  way, that is to find the x- and y-intercept:

1. To find x-intercept, let y be 0.
2x=4
  x=2, so x-intercept is at (2,0)

2. To find y-intercept let x be 0.
Y=4, so y-intercept is at (0,4)

The purpose of finding the coordinates of a line is to plot the line. No need to do multiple solutions. Just plot the x- and y-intercept, then connect...:)

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