There are several ways to show this.
1. You can compare the slopes from any point to the other two. (Too much arithmetic and fractions fro my taste.)
2. You can graph the points and see if they line up.
3. You can write the equation for the line and see of the point satisfies it. We'll do that here.
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The given points are the line's intercepts, so we can write the equation in intercept form as
.. x/2 +y/4 = 1
..2x +y = 4 . . . . . . . Multiply by 4 to get the standard form equation for the line
Now, it is easy to check the offered point.
.. 2(-25) +81 = -50 +81 = 31 ≠ 4 . . . . . . . . the point is not on the line.
