因式分-2x的平方+4x-1
=-2(x²-2x+1-3/2)
=-2[(x-1)²-6/4]
=-2(x-1+√6/2)(x-1-√6/2)

解不等式：（根号2）x>（根号3）x+1
-1>( √ 3-√2)x
x