Hej!
(x + 8)² = x² + 2 • x • 8 + 8² =
= x² + 16x + 64
(3x + 1)² = (3x)² + 2 • 3x • 1 + 1² =
= 9x² + 6x + 1
(5x + 4y)² = (5x)² + 2 • 5x • 4y + (4y)² =
= 25x² + 20xy + 16y²
(a + 9x)² = a² + 2 • a • 9x + (9x)² =
= a² + 18ax + 81x²
Pozdrawiam! - Julka
