The first step to solving an equation like this is to find the slope of a line that will be perpendicular to the line given. The slope of a line that's perpendicular to another line is the negative reciprocal. The negative reciprocal of -1/5 is 5. So, so far our equation is y = 5x + b. Now, to find what b is equal to, we should substitute the values of x and y from the point (1,2) since we know that our line goes through the point. Our equation becomes:
2 = 5 + b
b= -3
That means that the equation of our new line is y = 5x - 3
After dividing & simplifying you will get u= 5/3.
