已知如图,在△ABC中,AB=AC,点M,N在AC上,且MB=MN,∠ABN=∠MBC,求∠NBC的度数

∠用"代替MN=MB"MBN="MNB"MNB="A + "ABN"MBN="A + "ABN∠ABN=∠MBC"ABC="ABN + "MBN +"MBC = 3"ABN + "AAB=AC"ABC = "C3角型内角和为180"A + "ABC + "C = "A + 2"ABC = "A + 2*(3"ABN + "A) = 6"ABN + 3"A =1802"ABN + "A = 60"A = "MNB - "ABN2"ABN + "MNB - "ABN = "ABN + "MNB = "MBC + "MBN = 60 = ∠NBC不会打因为所以。只好这样啦~应该这样吧~如果有更简单的方法记得打出来啊~