Answer: C) 4/7
Step-by-step explanation:
The given equation is in the form y = mx+b with slope m = -7/4
Take the negative reciprocal of this to get 4/7. We simply flip the fraction and the sign (from negative to positive).
Note that multiplying any original slope with its perpendicular counterpart, will always get you -1
(-7/4)*(4/7) = -1
This applies to lines that are not vertical and not horizontal.