SOLUTION: A line with a slope of 3 travels through the coordinates (5, a) and 2a, 7). Find the value of a.

Algebra ->  Graphs -> SOLUTION: A line with a slope of 3 travels through the coordinates (5, a) and 2a, 7). Find the value of a.      Log On


   

Question 1099792: A line with a slope of 3 travels through the coordinates (5, a) and 2a, 7). Find the value of a.
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!

Slope is rise (change in y value) divided by run (change in x value):
+m+=+%28y%5B2%5D-y%5B1%5D%29+%2F+%28x%5B2%5D-x%5B1%5D%29+
Plugging in known values:
+3+=+%287-a%29%2F%282a-5%29+
+6a-15+=+7-a+
+7a+=+22+
+highlight%28a+=+22%2F7%29+
—
Check: (7-(22/7)) / ((44/7)-5) = (49-22)/(44-35) = 27/9 = 3 (ok!)