The slope of a perpendicular line to the original equation is the opposite reciprocal of the slope of the original equation. This makes the opposite reciprocal -3, so the slope of the perpendicular line is -3.
Now that we have found the slope, we will put it into the formula for slope, y = mx + b. This results in getting y = -3x + b.
We know the values for x and y, (1,2) respectively. Plug these values into y = -3x + b.
2 = -3(1) + b
b = 5
This means that 5 is your y intercept and goes into place for b
