Simplify the expression (-13)+(-2y)+(-7)-4y

Which of the following is a solution of z^6 = 64i? 2(cos105° + isin105°) 2(cos120° + isin120°) 2(cos135° + isin135°) 8(cos15° + isin15°)

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g