What is the value of Arc sine (StartFraction StartRoot 2 EndRoot Over 2 EndFraction)?

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?

50 points~ ! i have to turn this in tomarrow

Y= 4x + 3 y = - 1 4 x - 5 what is the best description for the lines represented by the equations?