Simplify -4r + s -2r -3s

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

Complete the solution of the equation. find the value of y when x equals -5. -4x - 8y = -52

20 points plus brainliest andwer plus my hover hoard im v desperate ! evaluate the polynomial for x=-2 in the equation -3x^3+7x^2-7x-1 (simplify your answer)