Four equivalent expressions for 100k-25k

Will give brainliest summations with algebraic expressions image shown

Marcus needs to rewrite f(x) = x2 + 6x + 4 in vertex form.

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?