(1)(2x²-7x+5)+(3x-1)-(x²-1) (2)x-3(1-2x+x²)+3(-2+3x-x²) (3)3a+二分之一(a-6b)-三(4)5a+(-2a)+｛a+1+(2a+a)+[a+1-(a+3)]｝
问题描述：
(1)(2x²-7x+5)+(3x-1)-(x²-1) (2)x-3(1-2x+x²)+3(-2+3x-x²) (3)3a+二分之一(a-6b)-三
(4)5a+(-2a)+｛a+1+(2a+a)+[a+1-(a+3)]｝
答
1. 2x 2;-7x+5 = 0 2 -5 1 -1 (2x-5)(x-1) = 0 , x = 5/2 , 1 2. 怎么有个Y？ 3. (2x-3) 2;-2x+3 = 0 (2x-
答
(1)(2x²-7x+5)+(3x-1)-(x²-1)=2x^2-7x+5+3x-1-x^2+1=x^2-4x+5(2)x-3(1-2x+x^2)+3(-2+3x-x^2)=x-3+6x-3x^2-6+9x-3x^2=-6x^2+16x-9(3)3a+1/2(a-6b)-3=3a+1/2a-3b-3=7/2a-3b-3(4)5a+(-2a)+｛a+1+(2a+a)+[a+1-...