The product of the slopes of the perpendicular lines is -1
That means if the slope of one of them is m, then the slope of the other is -1/m
(we reciprocal it and change its sign)
The given equation is
The slope of the line of the equation y = mx + b is m
Then the slope of the given line is -4
To find the slope of the perpendicular line to it, reciprocal it and change its sign
Then the slope of the perpendicular line is
Substitute it in the form of the equation
To find b we will use the given point (4, 7) which lies on the perpendicular line
Substitute x by 4 and y by 7 in the equation
Substitute the value of b in the equation
The answer is y = 1/4x + 6
The answer is the last choice