IQ tests are standardized and follow a normal distribution. On a common IQ test, the mean score is 100 with a standard deviation of 15. a) What is the probability that a randomly selected individual gets a score of 105 or higher

Solve each quadratic equation by factoring and using the zero product property. x^2 + 18x = 9x

Math i have no idea how to do a and b

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)