Y = x - 28/5. The slope here is 1. A perpendicular line will have a negative reciprocal slope. So our perpendicular line will have a slope of -1.
slope = (y2 - y1) / (x2 - x1) (k,2)....x1 = k and y1 = 2 (7,0)...x2 = 7 and y2 = 0 sub slope = (0 - 2) / (7 - k) slope = -2 / ?......now if we want the slope to be -1..that means the number where the question mark is has to be 2....for that to happen, k has to be 5...because 7 - 5 = 2.
Remember that perpendicular lines have inverse slopes, this means that they have the same number but with different signs, the line y=x-28/5 has a slope of 1 since 1 is the number that is multiplying the x, so the slope of the perpendicular line should be -1.
To calculate the value of K we need to use the formula for slope:
We insert the values into the formula and clear for K: