问题
填空题
已知x1,x2为方程x2+4x+2=0的两实根,则x13+14x2+55=______.
答案
x13+14x2+55=x1•x12+14x2+55=x1•(-4x1-2)+14x2+55
=-4x12-2x1+14x2+55
=-4(-4x1-2)-2x1+14x2+55
=14(x1+x2)+63
=-56+63=7
故答案为:7
已知x1,x2为方程x2+4x+2=0的两实根,则x13+14x2+55=______.
x13+14x2+55=x1•x12+14x2+55=x1•(-4x1-2)+14x2+55
=-4x12-2x1+14x2+55
=-4(-4x1-2)-2x1+14x2+55
=14(x1+x2)+63
=-56+63=7
故答案为:7