Which operations is the following set closed under: {2, 4, 6, }?

Given f(x) = 10x + 4 and g(x) = 3x - 8, what is f(x) + g(x) ? - 7x - 4 - 13x + 4 - 7x + 4 - 13x - 4

Atheater wants to build movable steps that they can use to go on and off the stage. they want the steps to have enough space inside so they can also be used to store props. how much space is inside the steps?

Segment an is an altitude of right δabc with a right angle at a. if ab = 2, squared 5 in and nc = 1 in, find bn, an, ac.