What is 21(2-x)+12x=44? how do i do that? !

You have to multiply everything in the parentheses by 21, so your new equation is
42-21x+12x=44
then reduce your x's on the left side, so -21+12 is -9, so your next equation would be 
42-9x=44
then subtract 42 from each side to get x by itself, so then you get 
-9x=2
then divide each side by -9, so then x=2/-9!

Hello! i hope this
since the cosine is the ratio of the adjacent side to the hypotenuse, you can see that cos 60° = ½. answer. according to the property of cofunctions (topic 3), sin 30° is equal to cos 60°. sin 30° = ½.