The number of possible combinations is given by
... C(18, 3) = 18!/(3!(18-3)!) = 18·17·16/(3·2·1) = 816 . . . . possible combinations
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There are 18 ways to choose the first one; 17 ways to choose the second one, and 16 ways to choose the 3rd one. The same 3 students can be chosen in any of 3! = 6 different orders, so the product 18·17·16 must be divided by 6 to get the number of possible combinations in which order doesn't matter.
In order to find the slope intercept form of the given coordinates above (-6,-3)(-9,-2) then you need to use the point slope formula :y-y1=m(x-x1) .now allyou have to due is to label each of the given coordinates x1,y1 and x2 ,y2.This will help with the differentiation of the given coordinates.Once you have done this apply the info within the formula ,and you will get an answer of :y= -1/3x - 5 ,and of course your slope is -1/3 and the y-intercept is -5 .
