Answer :

To solve for the value of [tex]\( a \)[/tex] given that [tex]\( b = 5 \)[/tex], we can follow these steps:

1. Identify the relationship between [tex]\( a \)[/tex] and [tex]\( b \)[/tex]: From the given options and the condition provided ([tex]\( b = 5 \)[/tex]), we need to determine which of the choices correctly represents the value of [tex]\( a \)[/tex].

2. Analyze the options: Let's review each option to see which correctly equates to [tex]\( a \)[/tex] when [tex]\( b = 5 \)[/tex].

- Option 1: [tex]\( b \)[/tex]
If [tex]\( a = b \)[/tex], and [tex]\( b = 5 \)[/tex], then [tex]\( a \)[/tex] would be 5.
[tex]\( a = 5 \)[/tex]

- Option 2: [tex]\( a \)[/tex]
This option is redundant as it states [tex]\( a \)[/tex] is just [tex]\( a \)[/tex], which doesn't provide any new information.

- Option 3: 10
This implies [tex]\( a = 10 \)[/tex], but there is no indication that [tex]\( a \)[/tex] should be 10 given [tex]\( b = 5 \)[/tex].

- Option 4: 5
This option suggests that [tex]\( a = 5 \)[/tex]. Given [tex]\( b = 5 \)[/tex], the value of [tex]\( a \)[/tex] being 5 is consistent with [tex]\( a \)[/tex] being equal to [tex]\( b \)[/tex].

- Option 5: [tex]\( \sqrt{5} \)[/tex]
This suggests [tex]\( a = \sqrt{5} \)[/tex], which seems unrelated to [tex]\( b = 5 \)[/tex] unless specified but doesn't directly follow from the given [tex]\( b = 5 \)[/tex].

- Option 6: [tex]\( 5 \sqrt{3} \)[/tex]
This implies [tex]\( a = 5 \sqrt{3} \)[/tex], which also seems unrelated to [tex]\( b = 5 \)[/tex].

3. Select the correct option: From our analysis and following the logical relationship [tex]\( a = b \)[/tex], the selection that holds true based on the given information [tex]\( b = 5 \)[/tex] is [tex]\( a = 5 \)[/tex].

Therefore, if [tex]\( b = 5 \)[/tex], the exact value of [tex]\( a \)[/tex] is:
[tex]\[ \boxed{5} \][/tex]