a-2b+1=0,所以 a-2b= -1,2b-a=1
3(a-2b)的2n次方-(2b-a)的2n-1次方+5-5(2b-a)的2n次方+2(a-2b)的2n-1次方-4
=3(a-2b)(a-2b)的2n-1次方-(2b-a)的2n-1次方-5(2b-a)(2b-a)的2n-1次方+2(a-2b)的2n-1次方+1
=[3(a-2b)+2](a-2b)的2n-1次方-[1+5(2b-a)](2b-a)的2n-1次方+1
=[3x(-1)+2](-1)的2n-1次方-(1+5x1)x1的2n-1次方+1
=(-1)(-1)的2n-1次方-6+1
=(-1)的2n次方-6+1
=1-6+1
= -4