Answer:
y = -7/4x + 61/4
Step-by-step explanation:
Step 1: Write equation in slope-intercept form
-7y = 9 - 4x
y = 4/7x - 9/7
Step 2: Find slope of perpendicular line
Take the negative reciprocal of the 1st equation
m = -7/4
Step 3: Write out known variables
y = -7/4x + b
Step 4: Find b
3 = -7/4(7) + b
3 = -49/4 + b
b = 61/4
Step 4: Rewrite equation
y = -7/4x + 61/4