Odpowiedź:
a)
V = 6x * 4x * 10 = 240x²
Pc = 2 (6x * 10 + 4x * 10 + 6x * 4x) = 2 * (60x + 40x + 24x²) =
= 2 * (100x + 24x²) = 200x + 240x²
b)
V = x(x + 1)(x + 3) = (x² + x)(x + 3) = x³ + 3x² + x² + 3x = x³ + 4x² 4x =
Pc = 2 [ (x + 1) * x + (x + 1)(x + 3) + x(x + 3) ] =
= 2 [ x² + x + x² + 3x + x + 4 + x² + 3x ] = 2 [ 3x² + 8x + 4 ] = 6x² + 16x + 8
