Question 176421
I just did one similar to that.

Write the equation of the line that passes through (4,-5) and (7,-3). Express in general form
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The hard way:
find the slope, m, = (diff in y)/(diff in x)
m = (-3 -(-5))/(7-4)
m = 2/3
Use either point:
y-y1 = m*(x-x1)
y+5 = (2/3)*(x-4)
3y+15 = 2x-8
2x-3y = 23
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Better way:
|x y 1|
|4 -5 1| = 0
|7 -3 1|
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x*(-5+3) - y*(4-7) + (-12+35) = 0
-2x + 3y + 23 = 0
2x - 3y = 23