Find the least common denominator (LCD) of 9/4 and 7/8

What is the perimeter, p, of a rectangle that has a length of x + 8 and a width of y − 1? p = 2x + 2y + 18 p = 2x + 2y + 14 p = x + y − 9 p = x + y + 7

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /

Atotal of 766 tickets were sold for the school play. they were either adult tickets or student tickets. there were 66 more student tickets sold than adult tickets. how many adult tickets were sold?