Posted by Anonymous on .
I have an assignment that asks me to write an equation in slopeintercept, pointslope, or standard form for the information given and to explain why the chosen form would be best. Below is the information given.
1. passing through (1,4) and (5,2)
2. that has slope 2 and y intercept 4
3. that has an xintercept of 6 and a yintercept of 3
4. that passes through (1,2) and has a slope of 5/3
I chose pointslope for the first one, slopeintercept for the second, slopeintercept for the third, and pointslope for the fourth. Do you think my answers are good, or would you choose different forms for some of them?

Algebra 
Reiny,
actually, any method should work for any of those conditions,
in #3, I would use the interceptintercept form
if the xintecept is 'a' and the yintercept is 'b', then the equation can be written simply as
x/a + y/b = 1
so x/6 + y/3 = 1
times 6
x + 2y = 6 , all done!
If I know the slope and a point, I use a method that given me the equation in about 3 lines
 based on the fact that for
Ax + By = C, the slope is A/B
if you give me the slope I can reverse that and start with the completed left side of the equation,
e.g.
given slope as 5/3 and the point (1,2) , your #4
the equation has to be
5x + 3y = C , but (1,2) lies on it, so
5(1) + 3(2) = C
C = 11
equation: 5x + 3y = 11
advantage, no fractions! 
Algebra 
Anonymous,
Thanks again!