Question

(2/5x + 5y)²
Помогите пожалуйста

Answer 1

$(\frac{2}{5}x + 5y)^2=(\frac{2}{5}x)^2+2\cdot\frac{2}{5}x\cdot5y+(5y)^2=\frac{4}{25}x^2+4xy+25y^2$