Question

What is the product? (9t − 4)(−9t − 4) −81t2 − 16 −81t2 + 16 −81t2 − 72t + 16 −81t2 + 72t + 16

Answer 1

Option 2nd is correct

`-81t^2+16`

Explanation:

To find the product of:

`(9t-4)(-9t-4)`

We can write this as:

`-(9t-4)(9t+4)`

Using identity rule:

`(a+b)(a-b) = a^2-b^2`

then;

`-((9t)^2-(4)^2)`

⇒
`-(81t^2-16)`

Using distributive property i.e,
`a \cdot (b+c) = a\cdot b+ a\cdot c`

`-81t^2+16`

Therefore, the following given product is,
`-81t^2+16`

Answer 2

`-81t^(2)+16`

Explanation:

we have

`(9t - 4)(-9t - 4)`

Applying distributive property

`(9t - 4)(-9t - 4)=(9t*-9t)+(9t*(-4))+(-4*(-9t))+(-4*(-4))\\=-81t^(2) -36t+36t+16\\=-81t^(2)+16`