Solve the following systems of equations

4x + y -2z = 0

2x - 3y + 3z = 9

-6x - 2y + z = 0

Simplify the following expressions

(6x^2 - 3x + 2) - (4x^2 + 2x - 5)

Simplify the following to the lowest term

x^3 - 1/x^4 - 1 * x^2 - 1/x^2 + x + 1

Solve the following equations

5/y+1 = 4/y+2

4/x^2 - x -12 + 1/x^2 - 9 = 2/x^2 - 7x + 12

Any help would be much appreciated! Thanks!!!