Definitions:
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Explanation: When dealing with writing equations when given only a point and the slope you will replace. The formula for the equation of a line is y=mx+b. The slope will replace the (mx) in the formula. If the poin that is given is the y-intercept then the y in the coordinate point will replace the (b) in the formula.
When dealing with writing equations when only 2 points are given you will need to use the formula (y2-y1)/(x2-x1) For this formula you will put the y from the second coordinate point and subtract it by the y in the first coordinate point , then you will put it over the x in the second coordinate subtracted by the x in the first coordinate. After that step you will divide the numberator by the denominator if the numbers are divisable such as 2/1.If the number are not divisable such as 3/5 then you will just leave the fraction as it is. |
Find the equation of a Line given That You Know two points it Passes Through. The equation of a line is typically written as y=mx+b where m is the slope and b is the y-intercept. Sources
Example problems: http://www.purplemath.com/modules/strtlneq.htm http://44329011-433237963675827832.preview.editmysite.com/uploads/4/4/3/2/44329011/1606842_orig.jpg |
Similarities: In both situations you will have to figure out the y-intercept if not given.
Differences; In one you are given a point and the slope and in another you are only given 2 coordinate point found on the line. |
In the slope-intercept form of a straight line, I have y, m, x, and b. So the only thing I don't have so far is a value for is b (which gives me the y-intercept). Then all I need to do is plug in what they gave me for the slope and the x and y from this particular point, and then solve for b:
(–6) = (4)(–1) + b –6 = –4 + b –2 = b |