(2x-7)(x-1)+(2x-3)(2x+3) 2(x-8)(x-5)-(2x-1)(x+2) 3x(3y-x)-(4x-3y)(x+3y)(2-b)(3+b)-(2-b)(2+b)1.(2x-7)(x-1)+(2x-3)(2x+3) 2.2(x-8)(x-5)-(2x-1)(x+2) 3.3x(3y-x)-(4x-3y)(x+3y)
(2x-7)(x-1)+(2x-3)(2x+3) 2(x-8)(x-5)-(2x-1)(x+2) 3x(3y-x)-(4x-3y)(x+3y)(2-b)(3+b)-(2-b)(2+b)1.(2x-7)(x-1)+(2x-3)(2x+3) 2.2(x-8)(x-5)-(2x-1)(x+2) 3.3x(3y-x)-(4x-3y)(x+3y)
(2x-7)(x-1)+(2x-3)(2x+3) 2(x-8)(x-5)-(2x-1)(x+2) 3x(3y-x)-(4x-3y)(x+3y)
(2-b)(3+b)-(2-b)(2+b)
1.(2x-7)(x-1)+(2x-3)(2x+3)
2.2(x-8)(x-5)-(2x-1)(x+2)
3.3x(3y-x)-(4x-3y)(x+3y)
(2x-7)(x-1)+(2x-3)(2x+3) 2(x-8)(x-5)-(2x-1)(x+2) 3x(3y-x)-(4x-3y)(x+3y)(2-b)(3+b)-(2-b)(2+b)1.(2x-7)(x-1)+(2x-3)(2x+3) 2.2(x-8)(x-5)-(2x-1)(x+2) 3.3x(3y-x)-(4x-3y)(x+3y)
1.
(2x-7)(x-1)+(2x-3)(2x+3)
=2x²-9x+7+4x²-9
=6x²-9x-2
2.
2(x-8)(x-5)-(2x-1)(x+2)
=2(x²-13x+40)-(2x²+3x-2)
=2x²-26x+80-2x²-3x+2
=-29x+82
3.
3x(3y-x)-(4x-3y)(x+3y)
=9xy-3x²-(4x²+9xy-9y²)
=9xy-3x²-4x²-9xy+9y²
=-7x²+9y²
4.
(2-b)(3+b)-(2-b)(2+b)
=(6-b-b²)-(4-b²)
=6-b-b²-4+b²
=-b+2
额..........我也无语
1.(2x-7)(x-1)+(2x-3)(2x+3) =2x*-2x-7x+7+4x*-3*=6x*-9x-2
*表示平方
(2x-7)(x-1)+(2x-3)(2x+3) 2(x-8)(x-5)……这里中间的这个2是(2x+3) 的2次幂呢还是中间少打了一个加号是2(x-8)?