SOLUTION: Find the value of x so the line that passes through (x, 5) and (12, 2) is perpendicular to the line that passes through (0, 1) and (2, 7).

Algebra ->  Linear-equations -> SOLUTION: Find the value of x so the line that passes through (x, 5) and (12, 2) is perpendicular to the line that passes through (0, 1) and (2, 7).       Log On


   

Question 444828: Find the value of x so the line that passes through (x, 5) and (12, 2) is perpendicular to the line that passes through (0, 1) and (2, 7).
Answer by rwm(914) About Me  (Show Source):
You can put this solution on YOUR website!
slope of second line
(7-1)/(2-0)
slope of first line
(5-2)/(x-12)
we want the two slopes multiplied to equal -1
(7-1)/(2-0)*(5-2)/(x-12)=-1
it looks harder than it is.
just do the math.
6/2*3/(x-12)=-1
9/x-12=-1
9=-1*(x-12)
-9=x-12
add 12
3=x