Question

5) Find the equation of the line going through the point (4,1) and

perpendicular to y = - 3x +7

Answer 1

3y=x-1 OR y=⅓x-⅓

Explanation:

Lets call the equation y=-3x+7 line l1

the other line passing through (4,1) l2

If two lines are perpendicular,then the product of their roots=-1

That is m(l1)×m(l2)=-1

Slope of l1=-3 therefore slope of l2=-1÷-3=⅓

Now that we have determined the slope of l2 we move on to find it's equation using the point-slope form

y-y1=m(x-x1)

y-1=⅓(x-4)

3y-3=x-4

3y=x-4+3

3y=x-1 OR y=⅓x-⅓