SOLUTION: What is the equation of a line, in general form, that passes through point (1, -2) and has a slope of 1/3. a. 3x - y - 7 = 0 b. x - 3y + 7 = 0 c. x - 3y - 7 = 0

Algebra ->  Linear-equations -> SOLUTION: What is the equation of a line, in general form, that passes through point (1, -2) and has a slope of 1/3. a. 3x - y - 7 = 0 b. x - 3y + 7 = 0 c. x - 3y - 7 = 0       Log On


   

Question 706274: What is the equation of a line, in general form, that passes through point (1, -2) and has a slope of 1/3.

a. 3x - y - 7 = 0
b. x - 3y + 7 = 0
c. x - 3y - 7 = 0

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
If you know point slope form, use it to make an equation for the line and then use properties of real numbers ("algebra steps") to put into slope intercept form (which is general form).
From formula for slope, m=%28y-y%5B0%5D%29%2F%28x-x%5B0%5D%29.
Clear the fraction,.... y-y%5B0%5D=m%28x-x%5B0%5D%29 which is point-slope form for a line.

Further, add y[0] to both sides: y=m%28x-x%5B0%5D%29%2By%5B0%5D,
carry out some of the other arithmetic,
y=mx-mx%5B0%5D%2By%5B0%5D
y=mx%2B%28y%5B0%5D-mx%5B0%5D%29. (Notice how I've kept all this in symbols so far.)

NOW, just substitute your given point and slope, and do any further computation to simplify.

y=%281%2F3%29x%2B%28-2-%281%2F3%29%2A1%29,
and you get
Final Answer: highlight%28y=%281%2F3%29x-%287%2F3%29%29

[You would be looking for choice #c. But none of those choices appear as "general form" for a line; they appear as a variation on standard form.]