定义新运算:X△Y=2X+Y,如果X△2X△3X△4X△5X=171,X值为()
X△2X△3X△4X△5X
=2X+2X△3X△4X△5X
=6X+3X△4X△5X
=12X+4X△5X
=20X+5X
=25X
X=171/25