Customer: "i buy the same items every week and my bill is normally $90.00. why am i now being charged $108.00 for the exact same items? " employee: "unfortunately, the increased cost of raw materials has forced us to increase our prices by "

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?