)1、x(2x+1)(1-2x)-4x(x-1)(1-x),其中x=-12、(3a-1)²-3(2-5a+3a
2个回答

1、x(2x+1)(1-2x)-4x(x-1)(1-x),其中x=-1

x(2x+1)(1-2x)-4x(x-1)(1-x)

= x(1+2x)(1-2x)+4x(x-1)(x-1)

= x【(1-4x²)+4(x-1)²】

= x【(1-4x²)+4(x²-2x+1)】

= x【1-4x²+4x²-8x+4】

= x(5-8x)

=-1×(5+8)

=-13

2、(3a-1)²-3(2-5a+3a²),其中a=-1/3

(3a-1)²-3(2-5a+3a²)

=(3a-1)²-3(3a-2)(3a-1)

=(3a-1)【(3a-1)-3(3a-2)】

=(3a-1)(3a-1-9a+6)

=(3a-1)(-6a+5)

=(-2)×7

=-14