Question

How do you simplify `(sqrta-4)(sqrta+4)`?

Answer 1

`a-16`

Explanation:

`(sqrta-4)(sqrta+4)`

Let's do each multiplication then add up the results:

`sqrtasqrta=a`
`sqrta(4)=4sqrta`
`(-4)sqrta=-4sqrta`
`(-4)(4)=-16`

`a+4sqrta-4sqrta-16=a-16`