Simplify cos (80) - sin (40).
cos (40) (cos (40) - sin (40))
sin (40) (2 cos (40) - 1)
1 - 8sin? (20) cos2 (20) - sin (40)
1 + 8sin2 (20) cos2 (20) + sin (40)

he has 140 chickens because he has 10 times more chickens than ducks and he has 14 ducks so 14*10=140

answer: 4  

the square root of 16 is 4. it is a very simple mathematic concept. a square root when a number multiplied by itself will result in a number. here, the number 16 comes when 4 is multiplied by 4. hence the square root of 16 is 4. you can always figure out a square root by the inverse operation of squaring.  

2 equivalent expressions to represent the area of a rectangle and the top is n-3 and the side is 2

area of the rectangle = length * width

given length = n - 3

width = 2

replace it in the area

so area of the rectangle = (n-3) *2

= 2(n-3)

one of the expression is 2(n-3)

to get another expression we distribute 2 inside the parenthesis

2(n-3) is 2n - 6

so another expression is 2n - 6

two equivalent expression are

2(n - 3)   , 2n - 6