(1/1+a²)+(1/1+b²)=（ab/ab+a²）+（ab/ab+b²）=b/a+b+（a/a+b）=a+b/a+b=1x²+x+(1/x²)+1/x=x²+1/x²+x+1/x=（x+1/x）²-2+5=28