Question

How do you multiply `(5 - 8y)^2`?

Answer 1

Multiplying `(5-8y)^2` gives `64y^2-80y+25`

Explanation:

Ok, so we start by rewriting it as two separate binomials.

`(5-8y)(5-8y)`

So now we multiplying the two binomials by the FOIL method. we have and get

`25-40y-40y+64y^2`

So we would double check our work to ensure we didn't miss multiplying a number by another number, otherwise it wouldn't come out right. So we can combine like terms and get:

`25-80y+64y^2`

But, you would want to put it to the highest degree first as some people would want that.

So the final answer is:

`64y^2-80y+25`

Answer 2

`(5-8y)^2 = (5-8y)(5-8y) = 64y^2 -80y +25`

Explanation:

To expand double brackets you need to multiply all of the terms in each bracket by the terms in the other bracket.

Applying the distributing rule `(a-b)^2 = a^2 - 2ab +b^2`)
So expanding this one you must do:

`-8y*-8y = 64y^2`
`(-8y*5)*2 = -80y`
and `5*5 = 25`

Add these terms together and you get the answer:

`64y^2 -80y +25`