ok i know these are a lot of problems but if someone could at least answer as much as you can please i’m having a really hard time trying to finish this assignment

Which expression is equivalent to 2x^2+7x+4?

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

X+y=-4 x-y=2 use elimination with adding and subtraction