Help I can't remember how to do this and I'm not sure that I'm right

Question

(5a+2)²

^{I think the answer is:}

25a⁴+4

Please help

Answer 1

Nope!

Remember this: to square a binomial, square the first plus twice the first times the 2nd plus the square of the 2nd.

In this case 25a² + 20a + 4