



 
Hi Tiffany, Then the slope m = (72)/(51) = 5/4. The point slope form of the equation is y  2 = (5/4)(x  1). When both sides are multiplied by 4 you get 4(y2) = 5(x1). After multiplying everything out and rearranging, this is the same as 5x + 4y = 3, or equivalently 5x  4y = 3. As a check on the work, plug in (1,2) and (5,7) and see that they satisfy
the equation(s)  the left hand side and the right hand side are equal.
Tiffany, There are many possible values for A, B and C that would be correct. Conventionally though, we usually choose an A that is positive (multiply both sides of your equation by 1 if A is negative and you'll solve that). As well, whenever possible we choose a set of A, B and C where they are all integers and there is no common divisor among them (in other words, the smallest set of integers that work). Stephen.  


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