Don't know this please help me

Which expression is equivalent to 5r6141 2r+st6

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?

What is the solution of |2x-5|< 21