Răspuns:
Explicație pas cu pas:
a) 4 × ( 2 x + 7 ) = 4 × 2 x + 4 × 7 = 8 x + 28
b - 3 ( 5 - 4x) = - 3 × 5 - 3 × ( - 4 x ) = - 15 + 12 x = 12 x - 15
c) x² · ( 7 x + 4 ) = x² · 7 x + x² · 4 = 7 x³ + 4 x²
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a) ( x + 5)² = x² + 2 · x · 5 + 5² = x² + 10 x + 25
-> aplic formula ( a + b)² = a² + 2ab + b²
b) ( 6 x - x)² = (5x)² = 5²·x² = 25 x²
c) ( 3 x - 1 )² = (3x)² - 2 · 3 x + 1² = 9 x² - 6 x + 1
