Multiply and simplify the following polynomials: \((3x^2 - 2x + 1)(x^2 + x - 2)\)

Step 1 ：First, distribute each term in the first polynomial to each term in the second polynomial. That is, \(3x^2 * x^2 + 3x^2 * x + 3x^2 * -2 - 2x * x^2 - 2x * x - 2x * -2 + 1 * x^2 + 1 * x - 1 * 2\)

Step 2 ：Simplify to get \(3x^4 + 3x^3 - 6x^2 - 2x^3 - 2x^2 + 4x + x^2 + x - 2\)

Step 3 ：Combine like terms to get \(3x^4 + x^3 - 7x^2 + 5x - 2\)