Question

已知x的平方-2x=2,将代数式(x-1)的平方+(x+3)(x-3)+(x-3)(x-1)先化简,再求值

Answer 1

原式=x²-2x+1+x²-9+x²-4x+3

=3x²-6x-5

=3(x²-2x)-5

=3×2-5

=1