Simplifying polynomials

Example 1: Simplify. x – 3x -y -11y -4x – 3
Solution 1: (x-3x-4x) plus (-y-11y) equals -6x -12y.

Example 2: simplify. 5(a-3b)-6(2a-3b)
Solution 2: 5a-15b-12a plus 18b) equals -7a plus 3b.

Example 3: expand and simplify 3(2x-3)(x-2)
Solution 3: 3(2 x squared -4x-3x plus 6) equals 6x squared -21x plus 18.