Question

Which shows a perfect square trinomial?

502-4x2
100-36x?y
16x2+24 xy +9y2
49x2 - 70 xy +10y​

Answer 1

Third choice.

Explanation:

Trinomial means you have 3 terms.

You don't have 3 terms in first two choices so let's not look at them.

Anything of the form
`a^2x^2+2abxy+ b^2y^2` is a perfect square trinomial because it can be written as
`(ax+by)^2`.

Let's this this:

`(ax+by)^2`

`(ax+by)(ax+by)`

Now foil!

First=ax(ax)=a^2x^2

Outer=ax*by=abxy

Inner=by*ax=abxy

Last=by*by=b^2y^2

Add together and this gives you a^2x^2+2abxy+b^2y^2.

So looking at third choice you can write it as 4^2x^2+24xy+3^2y^2.

Is 2*4*3 equal to 24? If it is then you have your answer. It is.

We have our answer.