Question : Simplify the following:
$\sin2x+2\sin4x+\sin6x$

Question : Simplify the following expression.
$(4 x + 1)^2 - (4 x + 3)(4 x - 1)$

Question : If $( x^{3}-y^{3}):( x^{2}+xy+y^{2})=5:1$ and $( x^{2}-y^{2}):(x-y)=7:1$, then the ratio $2x:3y$ equals:

Question : What is the solution of the following equations?
2x + 3y = 12 and 3x – 2y = 5

Question : Simplify the expression $\frac{\sqrt{x}-\sqrt{y}}{\sqrt{x}+\sqrt{y}}$, where $x=2$ and $y=3$.