Calling all awesome geeks! Calc 3 questions.

How do you graph parametric equations?

I.E x(t)= 5cos(t) - cos(5t)

y(t)= 5sin(t) - sin(5t)

Also how do you solve multiply equations with multiple variables?

I.E. 7x+ 6y+ 9z= 0

5x+ 6y+ 20z= 0

x+ y+ z= 0

Last one! When I integrate the Sq root of [(-12sin(3x))^2+ (12cos(3x))^2 and you are integrating it from 0 to 2(pie)/3 ( I have no pie symbol on the computer... awesome)I get a question mark. But when I integrate it by hand I get 8(pie). Any help would be much appreciated!