7/4+1/5×-3/2=4/5× i need solving this. the answer is {5\12} but i keep getting 29/12

Study results indicate that the mean length of time people spend on a bus in a city is between 21.2 min and 24.5 min what is the study margin of the error?

Given: pb tangent pv,pu secants if m = 80° and m = 30°, then m 3 = 55 40 25

Write an expression that is equivalent to ( 3+14)+27.