Equations of a straight line

Question

A straight line L passes through the point w/ cords (4,7) and its perpendicular to the line with equation y = 2x + 3. Find the equation of the line L.

Answer 1

Hi Beth

The slope of a perp. line is the negative reciprocal of  2, or  -1/2.

thus  y=-1/2x + b.   To find  b   substitute (4,7) for x  and y.

        7=-1/2(4) +b

        7=-2        +b---->  b=9

 

Ans.  y=-1/2x +9