Answer:
value of a is, 81
Step-by-step explanation:
Using the identity rule:
[tex](a+b)(a-b)=a^2-b^2[/tex]
Given the equation:
[tex](9x-4)(9x+4)=ax^2-b[/tex]
Apply the identity rule:
[tex](9x)^2-(4)^2=ax^2-b[/tex]
⇒[tex]81x^2-16=ax^2-b[/tex]
On comparing both sides we have;
[tex]a = 81[/tex] and b = 16
Therefore, the value of a is, 81
