Question

1.设 ：a方+b方=14,ab=1,a=2a方-ab+b方,b=a方-3ab+2b.求A+B的值.

Answer 1

a²+b²=14 ab=1 a=2a²-ab+b² b=a²-3ab+2b²

a+b=2a²-ab+b²+a²-3ab+2b²=3a²+3b²-4ab=3×14-4=38

AX的5次方+BX³+CX+2=32A+8B+2C+2=-3

X=-2

AX5次方+BX³+CX+2=-32A-8B-2C+2=-(32A+8B+2C+2)+4=-3+4=1