Answer :

Sure, let's simplify the given expressions step by step:

### Simplification of [tex]\(\frac{a^5}{a^{11}}\)[/tex]:

1. Identify the exponent rule for division: When you divide like bases, you subtract the exponents. The rule is [tex]\( a^m / a^n = a^{m-n} \)[/tex].

2. Apply the rule: Here, [tex]\( m = 5 \)[/tex] and [tex]\( n = 11 \)[/tex].
[tex]\[ \frac{a^5}{a^{11}} = a^{5-11} \][/tex]

3. Calculate the exponent:
[tex]\[ 5 - 11 = -6 \][/tex]

4. Write the result:
[tex]\[ a^{-6} \][/tex]

So, [tex]\(\frac{a^5}{a^{11}} = a^{-6}\)[/tex].

### Simplification of [tex]\(\frac{5^{11}}{5^{12}}\)[/tex]:

1. Identify the exponent rule for division: When you divide like bases, you subtract the exponents. The rule is [tex]\( 5^m / 5^n = 5^{m-n} \)[/tex].

2. Apply the rule: Here, [tex]\( m = 11 \)[/tex] and [tex]\( n = 12 \)[/tex].
[tex]\[ \frac{5^{11}}{5^{12}} = 5^{11-12} \][/tex]

3. Calculate the exponent:
[tex]\[ 11 - 12 = -1 \][/tex]

4. Write the result:
[tex]\[ 5^{-1} \][/tex]

So, [tex]\(\frac{5^{11}}{5^{12}} = 5^{-1}\)[/tex].

### Summary of the Solutions:
[tex]\[ \frac{a^5}{a^{11}} = a^{-6} \][/tex]
[tex]\[ \frac{5^{11}}{5^{12}} = 5^{-1} \][/tex]