>>78
とりあえず(1)だけ
(1)X^2+2X-1=0 X<=0 よりX=-1-√2
X^10+2X^9-X^8+2X^2+3X+2=X^8(X^2+2X-1)+2(X^2+2X-1)-X+4
=-x+4=-(-1-√2)+4
=5+√2