Question

(25+8)^2-(8^2+25^2)=_

Please help! Thanks, no spam, ty!
solve it without using a calculator if best, I think there is a trick to solving this but I don't know.

Answer 1

(25+8)^2-(8^2+25^2)
(33)^2-(64+625)
1089-689
400

Answer 2

Like in your earlier question, we'll use the identity

(a + b)² = a² + 2ab + b²

to write

(25 + 8)² = 25² + 2•25•8 + 8²

Then

(25 + 8)² - (8² + 25²) = 2•25•8 = 400