I'm having a complete mind blank..and can't do these two questions...

any help would be greatly appreciated.

1) By writing sin3x as sin (2x+x) show that sin 3x = 3sinx - 4sin(cubed)x

i know that sin(2x+x) = sin2xcosx + cos2xsinx but i don't know where to go from there.

2) f(x) = 1-3+3x does not = -2

x+2 (x+2)squared

show that f(x) =x(squared) + x + 1x does not = -2

(x+2)squared

please help if you can do either of these.

thanks