For this case we have the following trinomial:
[tex]x^2 - 10x + a
[/tex]
We must complete squares to make it a perfect trinomial.
Therefore, the value of a is given by:
[tex]a = (-10/2) ^ 2
[/tex]
Rewriting:
[tex]a = (-5) ^ 2
a = 25[/tex]
Then, the polynomial is:
[tex]x ^ 2 - 10x + 25
[/tex]
Rewriting as a perfect square:
[tex]x ^ 2 - 10x + 25 = (x - 5) ^ 2
[/tex]
Answer:
The value of a is:
a = 25