What is the law of cosines and how do I use it to find an angle when I am given side A side C and angle A?

Complete the square to determine the minimum or maximum value of the function defined by the expression. x2 − 12x − 2 a) maximum value at 38 b) minimum value at 38 c) maximum value at −38 d) minimum value at −38

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If x + 10 = 70, what is x? a. 40 b. 50 c. 60 d. 70 e. 80