Identify the trinomial to factor: \(z^2 - 11z + 30\).
Look for two numbers that multiply to the constant term \(30\) and add up to the coefficient of the middle term, which is \(-11\).
List the factor pairs of \(30\): \((1, 30)\), \((2, 15)\), \((3, 10)\), and \((5, 6)\), and consider their signs to sum to \(-11\).
Since the middle term is negative and the constant is positive, both numbers must be negative. Check which pair of negative numbers multiply to \(30\) and add to \(-11\): \(-5\) and \(-6\).
Write the factored form using these numbers: \((z - 5)(z - 6)\).