Răspuns:
Explicație pas cu pas:
a) ( x - 1 )² = x² - 2 x + 1 → aplic formula (a-b)² = a²- 2 ab + b²
b) ( x-4)(x+4) = x² - 16 →aplic formula (a-b)(a+b) = a² - b²
c) (3x-2)² = 9 x² - 12 x + 4
= (3x)² - 2 × 3 x × 2 + 2² = 9 x² - 12 x + 4
d) ( 2 x² + x + 1 )² = 4 x⁴ + 4 x³ + 5 x² + 2 x + 1
= ( 2 x² + x + 1 ) ( 2 x² + x + 1 ) =
= 4 x⁴ + 2 x³ + 2 x² + 2 x³ + x² + x + 2 x² + x + 1 =
= 4 x⁴ + 4 x³ + 5 x² + 2 x + 1
