### 11.8.3 Subtraction in ℤ/pℤ or in ℤ/pℤ[x]

The - operator subtracts two integers in ℤ/pℤ or two polynomials in ℤ/pℤ[x]. (See also Section 7.3.2.) For polynomial expressions, use the normal command to simplify.

#### Examples

For integers in ℤ/pℤ:

31%13-10%13

| ⎛ ⎝ | −5 | ⎞ ⎠ | %13

For polynomials with coefficients in ℤ/pℤ:

normal((11*x+5)%13-(8*x+6)%13)

or:

normal(11%13*x+5%13-(8%13*x+6%13))

| ⎛ ⎝ | 3%13 | ⎞ ⎠ | x+ | ⎛ ⎝ | −1 | ⎞ ⎠ | %13