Anonymous asked in Science & MathematicsMathematics · 1 decade ago

How did they arrive at this answer?

Graph each equation on the coordinate grid.

1) y= 3x -4 The answer is (0,-4) , (1,-1)

2) x - 2y = 1 The answer is (1,0) (3,1)

3) -4 = y +2 The answer is (2,-4) (1,-3)

The GED book missed out on the steps

Thank You

3 Answers

  • 1 decade ago
    Favorite Answer

    1.) y=3x-4

    3 is your slope and -4 is your y intercept (where the line crosses the y axis). I always make a "t" chart and sub values in for x. (Or you can sub value in for y and get x)

    X | Y

    0 | -4**********Sub. zero in for x and y=-4

    1 | -1**********Sub one in for x and y=-1

    2 | 2**********Sub two in for x and y=2

    -3 | -13*********Sub -3 in for x and y=-13

    -10 | -34*********Sub -10 in for x and y=-34

    2.) The same principle applies only you need to set your equation up in standard form: y=mx+b

    To do this take your x term across the equal sign and subtract it from 1: -2y=1-x

    Now take your -2 across the equals sign and divide it by each term: y = -1/2 + X/2

    Now make a "t" chart and start substituting those values in for x.

    3.) The third equation I came up with a different solution from the book, so I'll leave that advice to someone else. I hope this helps!

    Good Luck!!!!

  • 1 decade ago

    The first is in slope-intercept form, -4 is the y-intercept so the first point is (0, -4), because thats where the line intercepts the y-axis, the second point is found by incrementing x by one, and then adding the slope to the y value of the y-intercept

    The second equation is in standard form. The first point is found by substituting y with 0, then you solve for x, so you get (1,0). The second point confuses me though, I think you increment y by one and x by 2, but I don't know why.

    The third is wierd, I've never heard of that form before, if you solve for y, it would be y = -6, but thats not the case with your points, so that's kinda wierd (maybe a typo you made?)

    Good luck

  • Dr M
    Lv 5
    1 decade ago

    This is by substitution

    Substitute any value for x you will get y

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