Răspuns:
Explicație pas cu pas:
→ aplic formula a² + 2 a b + b² = ( a + b )²; respectiv
formula a² - b² = ( a - b ) ( a + b )
x² + 8 x + 16 = ( x + 4 )²
9 x² + 12 x + 4 = ( 3 x + 2 )²
36 x² - 60 x + 25 = ( 6 x - 5)²
4 x² - 12 x + 9 = ( 2 x - 3 )²
4 x² - 25 = ( 2 x + 5 ) ( 2 x - 5 )
144 - 25 x² = ( 12 - 5 x ) ( 12 + 5 x )
9 x² + 12 x + 4 = ( 3 x + 2)²
4 x² + 20 x + 25 = ( 2 x + 5 )²
