How many numbers must be selected from the set {1, 2,3,4,5,6}to guarantee that at least one pair of these numbers add up to 7

Ill mark the brainliest if you me with the these three questions 7,8,9

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.

Write an equation of the line that passes through the point (2, 3) and is perpendicular to the line x = -1. a) y = 1 b) y = 3 c) y = 0 eliminate d) y = -3