解:X的平方大于等于2x减2
设 ①y1=x²
②y2=2x-x,做函数y1,y2直角坐标系图。得,如图:
可知:x∈(-∞,+∞)
解:X²≥2X-2X²-2X+2≥0X²-2X+1+1≥0(X-1)²+1≥0(X-1)²≥0,1>0,则X²≥2X-2在全体实数上成立.所以原不等式的解集为R
x^2≥2x-2,x^2-2x+2≥0,即(x-1)^2+1≥0,其解集是R.