Question

What is (ab-9)(ab+8)

Answer 1

It's an expression that's made out of the product of two binomials.

When the indicated multiplication is carried out, the expression reads:

a²b² - ab - 72

Answer 2

`(ab-9)(ab+8) = {(ab)}^(2) - ab - 72`

Step-by-step explanation

We want to expand (ab-9)(ab+8)

We use the distributive property to obtain,

`(ab-9)(ab+8) = ab(ab+8)-9(ab+8)`

Expand:

`(ab-9)(ab+8) = {(ab)}^(2) +8ab-9ab - 72`

Combine the middle terms to get;

`(ab-9)(ab+8) = {(ab)}^(2) - ab - 72`

Or

`(ab-9)(ab+8) = a^2b^2 - ab - 72`