Odpowiedź:
1)
2(3t + 2)^2 - 5(2t -3)(2t+3) - (t-7)^2
2(9t^2 + 12t + 4) - 5(4t^2 - 9) - (t^2 - 14t + 49)
18t^2 + 24t + 8 - (20t^2 - 45) - t^2 + 14t - 49
18t^2 + 24t + 8 - 20t^2 + 45 - t^2 + 14t - 49
- 3t^2 + 38t + 4
A więc to będzie odpowiedź D.
2)
a) 5a^2 - 12ab + 7b^2 - 4ab + 10a^2 - 3b^2 = 15a^2 - 16ab + 4b^2 - stopień 2
b) 3p^2 +3pq - (100p - 40q) - (12pq + 20q^2) = 3p^2 +3pq - 100p + 40q - 12pq - 20q^2 = 3p^2 - 20q^2 9pq - 100p + 40q - stopień 2
c) 2(x^2 - 4xy + 4y^2) + 4(9x^2 - 4y^2) - (16x^2 - 8xy - y^2) = 2x^2 - 8xy + 8y^2 + 36x^2 - 16y^2 - 16x^2 + 8xy + y^2 = - 7y^2 + 20x^2 + 8xy - stopień 2
3)
P = (3x + 2y)^2 + (x+y)^2 = 9x^2 + 12xy + 4y^2 + x^2 + 2xy + y^2 = 10x^2 + 14xy + 5y^2
Obwód = 3(3x + 2y) + 2(x+y) = 9x + 6y + 2x + 2y = 11x + 8y
Szczegółowe wyjaśnienie:
