(−5x + 4) − (3x2 − 7x + 4) simplified and written in standard form?

Samantha swam upstream for some distance in one hour. she then swam downstream the same river for the same distance in only 12 minutes. if the river flows at 4 mph, how fast can samantha swim in still water?

Give the equations of two different lines that are perpendicular to the line 3x + 4y = 7.

It says factor each expression 49x-28?