Question 397360
If the line
y=A+B(x-3)
is perpendicular to the line
y=2x
and
it contains the point
(5,15)
, what are the values of
A and B? 

y=A+B(x-3)
This equation is a straight line of the standard form, y=mx+b, with m being the slope and b the y-intercept.
In the given equation, B is the slope and A, the y-intercept.
This line is perpendicular to another line, y=2x, whose slope=2.
The negative reciprocal of this slope is the slope of the given line which would be -1/2 which is also equal to B
The equation now reads y=-1/2(x-3)+A
To find A, use the (x,y) coordinates given, and solve for A.
15=-1/2(5-3)+A
15=-1+A
A=16
The equation now reads, y=(-1/2)(x-3)+16 

Ans: 
B=-1/2
A=16