Answer:
Step-by-step explanation:
y = mx + b for line through (7, 4) and perpendicular to -5x + 9y = - 71
perpendicular lines have negative reciprocal slopes
-5x + 9y = - 71
9y = 5x - 71
y = (5/9)x - 71/9
so a perpendicular line will have slope -9/5
y = (-9/5)x + b
plug in our desired point
4 = (-9/5)7 + b
4 = -63/5 + b
20/5 = -63/5 + b
b = 83/5
y = (-9/5)x + 83/5
5y = -9x + 83
