Answer: -2/3
Step-by-step explanation:
I wrote the equation y-3=3/2(x-4) in slope-intercept form. It's y=3/2x-5, so the slope is 3/2.
To find the perpendicular slope, I found the opposite reciprocal. The reciprocal of 3/2 is 2/3 and the opposite of 2/3 is -2/3
