Odpowiedź:
zad 9
a)
P - pole = 1/2 * (4a + 3b)(3a - b) = 1/2 * (12a² + 9ab - 4ab - 3b²) =
= 1/2(12a² + 5ab - 3b²) = 12a²/2 + 5ab/2 - 3b²/2 = 6a² + 2,5ab - 1,5b²
b)
P - pole = 1/2(4a + 2b)(3a - 1) = 1/2(12a² + 6ab - 4a - 2b) =
= 12a²/2 + 6ab/2 - 4a/2 - 2b/2 = 6a² + 3ab - 2a - b
