Which equation represents a line that is perpendicular to the line whose equation is y = 4x + 12?
y = 4x + 4
y = -4x + 7
y = (-1/4x) + 1
y = (1/4x) + 9

Abari owns 100 shares of stock a and 45 shares of stock b. for the past month, his stocks have been fluctuating inversely. stock a decreased by m cents per share and stock b increased by n cents per share. which equation can be used to find the total change in value of jabari's shares per month?