y = x + 10 has slope = 1
perpendicular lines, slope is opposite and reciprocal
so perpendicular line slope = -1
passes through the point (15, –5)
y = mx + b
-5 = -1(15) + b
b = -5 + 15
b = 10
y -intercept : 10
The equation of the line in slope-intercept form is y = -x + 10
