Answer:
y = x - 9
Step-by-step explanation:
Keep in mind that the lines t and u are perpendicular, which implies that their slopes are negative reciprocals of one another. The negative reciprocal of the slope -1 of line t is +1.
Thus we need to find the equation of line u, knowing that the slope of this line is +1. Starting with the slope-intercept form y = mx + b, we find b:
y = mx + b becomes
-8 = (+1)(-1) + b, or -8 =-1 + b. Then b = -9, and the desired equation is
y = x - 9
