Tell whether the statement is always, sometimes, or never true for real numbers a, b, and c. (a+ b) + c = a + (b + c)

Average acceleration: i have no idea how to do this.

Sketch the region enclosed by the given curves. decide whether to integrate with respect to x or y. draw a typical approximating rectangle and label its height and width. y= 5x, y=7x^2then find the area s of the region.

The function f(x)= -(x+5)(x+1) is down. what is the range of the function?