# If (8z-9) (8z+9) = az^{2}-b, what is the value of a?

**Solution:**

Given (8z-9) (8z+9) = az^{2}-b

This is of the form of the algebraic identity a^{2}- b^{2} = (a+b) (a-b)

Expand the terms in product

64z² -72z +72z -81 = az² -b

Here, -72z and +72z get cancelled

⇒ 64z² -81 = az² -b

By comparing the terms and the equal power of z and constant,

We get, a = 64 and b = 81

## If (8z-9) (8z+9) = az^{2}-b, what is the value of a?

**Summary: **

If (8z-9) (8z+9) = az^{2}-b, the value of a is 64.