Prove that(AuB)'=A'nB'

This is different from the first one can someone me

Which number completes the inequality? 2/3 < _ < 7/9

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.