תשובה אחת
(1) ==> a = - (b + c)
(2) ==> b^2 + 2bc + c^2 + b^2 + c^2 = 74
==> 2b^2 = 74 - 2bc - 2c^2
==> b^2 = 37 - bc - c^2
(3) = (b + c)^4 + (37 - bc - c^2)^2 + c^4 =
= b^4 + 4b^3c + 6b^2c^2 + 4bc^3 + c^4 + 37^2 - 37bc - 37c^2 + b^2c^2 + bc^3 + c^4 + c^4 =
= b^4 + 4b^3c + 7b^2c^2 + 5bc^3 + 3c^4 - 37 (bc + c^2 - 37)
(2) ==> b^2 + 2bc + c^2 + b^2 + c^2 = 74
==> 2b^2 = 74 - 2bc - 2c^2
==> b^2 = 37 - bc - c^2
(3) = (b + c)^4 + (37 - bc - c^2)^2 + c^4 =
= b^4 + 4b^3c + 6b^2c^2 + 4bc^3 + c^4 + 37^2 - 37bc - 37c^2 + b^2c^2 + bc^3 + c^4 + c^4 =
= b^4 + 4b^3c + 7b^2c^2 + 5bc^3 + 3c^4 - 37 (bc + c^2 - 37)
באותו הנושא: