What is the sum of r+s, when r = –14.1 and s = 18.3?
a. –32.4
b. –4.2
c. 4.2
d. 32.4

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?

For problems 29 - 31 the graph of a quadratic function y=ax^2 + bx + c is shown. tell whether the discriminant of ax^2 + bx + c = 0 is positive, negative, or zero.

The vertices of a triangle are a(7.5), b(4,2), and c19. 2). what is