SOLUTION: Find s if the line joining (2,6) to (s+4,s) is parallel to the line joining (5,3) and (-2,0).

Algebra ->  Inequalities -> SOLUTION: Find s if the line joining (2,6) to (s+4,s) is parallel to the line joining (5,3) and (-2,0).      Log On


   

Question 35651: Find s if the line joining (2,6) to (s+4,s) is parallel to the line joining (5,3) and (-2,0).
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
If the two lines are parallel then their slopes must be equal. Remember that slope = m+=+%28RISE%29%2F%28RUN%29+.

If lines are parallel, then %28RISE%29%2F%28RUN%29+=+%28RISE%29%2F%28RUN%29+.

%28s-6%29%2F%28s%2B4-2%29+=+%280-3%29%2F%28-2-5%29
+%28s-6%29%2F%28s%2B2%29+=+%28-3%29%2F%28-7%29
+%28s-6%29%2F%28s%2B2%29+=+3%2F7

Since a%2Fb=c%2Fd means that a%2Ad=b%2Ac, it follows that
+%28s-6%29%2F%28s%2B2%29+=+3%2F7 means that 7%28s-6%29+=+3%28s%2B2%29+.

7s+-+42+=+3s+%2B+6

Subtract 3s from each side, and add +42 to each side
4s=+48
s+=+12

To avoid public embarrassment, perhaps I should check this. The two points that were given in terms of s were (2,6) to (s+4,s), which if s = 12, would be (2,6) to (16,12). The slope between these would be %2812-6%29%2F%2816-2%29+=+6%2F14+=+3%2F7. This is the same as the other slope, so it checks.

R^2 at SCC