问题
填空题
已知,a+b=4n+2,ab=1,若19a2+147ab+19b2的值为2009,则n=______.
答案
∵19a2+147ab+19b2
=19(a+b)2+109ab
=19(4n+2)2+109
=2009,
(4n+2)2=100
故4n+2=±10
解得n=2或n=-3
故答案为:2,或-3
已知,a+b=4n+2,ab=1,若19a2+147ab+19b2的值为2009,则n=______.
∵19a2+147ab+19b2
=19(a+b)2+109ab
=19(4n+2)2+109
=2009,
(4n+2)2=100
故4n+2=±10
解得n=2或n=-3
故答案为:2,或-3