The position of an object moving along a line is given by the function s(t) = -7t^2 + 21(t). find the average velocity of the object over the following intervals
the average velocity of the object over the interval [1, 1 + h] is ?

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?

A+b= 17, ab=70, find the value of |a-b|

Arrange the steps to solve this system of linear equations in the correct sequence. x + y = -2 2x – 3y = -9 tiles subtract 3x + 3y = -6 (obtained in step 1) from 2x – 3y = -9 (given) to solve for x. substitute the value of x in the first equation (x + y = -2) to get y = 1. the solution for the system of equations is (-3, 1). x = -15 the solution for the system of equations is (-15, 13). add 3x + 3y = -6 (obtained in step 1) to 2x – 3y = -9 (given), and solve for x. x = -3 substitute the value of x in the first equation (x + y = -2) to get y = 13. multiply the first equation by 3: 3(x + y) = 3(-2) 3x + 3y = -6.