(2-5x) totul la pătrat
(3x-1/2)totul la pătrat


Răspuns :


(2-5x)²=2²-2·2·5x+(5x)²
=4-20x+25x²

(3x- [tex]\frac{1}{2}[/tex])²=(3x)²-2·3x· [tex]\frac{1}{2}[/tex]+ ([tex]\frac{1}{2}[/tex])²

=9x²-3x+ [tex]\frac{1}{4}[/tex]
(2 - 5x)² = 2² - 2×2×5x + (5x)² = 4 - 20x + 25x²

(3x - 1/2)² = (3x)² - 2×3x×1/2 + (1/2)² = 9x² - 3x + 1/4