Question 670979
Perhaps, the (2, 4) is the coordinant through which another line passes.
That other line may be parallel or perpendicular to the given line.
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Parallel lines have the same slope.
Perpendicular lines have negative inverse slopes
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You would use the slope of the given line with the coordinates to solve for the y-interecept.  Then you can write the equation of the "other" line.
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You may be asked if those coordiantes (2, 4) are on that line.
{{{4 = 3x + 8, so 4 - 8 = 3x, so x = -4/3 <> 2}}}
({{{-4/3}}}, 4)
Hence, (2, 4) would not be a point on the line.
Alternatively,
y = 3(2) + 8 = 6 + 8 = 14
(2, 14)
Again, (2, 4) is proven not to be on that line.
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