【(2x+3)(2x-3)-7x(x-3)+(2x-3)^2】÷(-2x)其中x=3

来源：学生作业帮助网编辑：作业帮时间：2024/05/03 05:55:56

【(2x+3)(2x-3)-7x(x-3)+(2x-3)^2】÷(-2x)其中x=3
【(2x+3)(2x-3)-7x(x-3)+(2x-3)^2】÷(-2x)其中x=3

【(2x+3)(2x-3)-7x(x-3)+(2x-3)^2】÷(-2x)其中x=3
【(2x+3)(2x-3)-7x(x-3)+(2x-3)^2】÷(-2x)
=【4X^2-9-7x^2+21X+4X^2-12X+9】÷(-2x)
=(X^2+9X)÷(-2x)
=(X+9)/-2
=(3+9)/-2
=-6

原式=x^2+9x=9+27=36

原式=(4x²-9-7x²+21x+4x²-12x+9)÷(-2x)
=(x²+9x)÷(-2x)
=-(x+9)/2
=-(3+9)/2
=-6

因为x=3，所以原式可化为如图所示：

还望采纳，谢谢~

【(2x+3)(2x-3)-7x(x-3)+(2x-3)^2】÷(-2x)
=[(2x+3)(2x-3)+(2x-3)^2-7x(x-3)]÷(-2x)
={(2x-3)[(2x+3)+(2x-3)]-7x(x-3)}÷(-2x)
=[4x(2x-3)-7x(x-3)]÷(-2x)
=[4(2x-3)-7(x-3)]÷(-2)
=[8x-12-7x+21]÷...

全部展开

【(2x+3)(2x-3)-7x(x-3)+(2x-3)^2】÷(-2x)
=[(2x+3)(2x-3)+(2x-3)^2-7x(x-3)]÷(-2x)
={(2x-3)[(2x+3)+(2x-3)]-7x(x-3)}÷(-2x)
=[4x(2x-3)-7x(x-3)]÷(-2x)
=[4(2x-3)-7(x-3)]÷(-2)
=[8x-12-7x+21]÷(-2)
=(x+9)÷(-2)
代入x=3得：
【(2x+3)(2x-3)-7x(x-3)+(2x-3)^2】÷(-2x)
=(3+9)÷(-2)
=-6
希望对你有帮助，望君采纳，谢谢~

收起

*-----------------------------------------------*| 6 4 X | 8 X X | X X 5 || X X X | X X X | X 7 8 || X X X | X X X | X X X ||---------------+---------------+--------------- || X X X | X X X | 5 1 X || X X X | X 6 X | X X X || 8 X X | 3 5 X | 2 X X || 填九宫格帮帮忙.x x 6 x x 7 x x 98 x x x 3 x 1 x x 9 x x 6 x 5 x 3 x x x 3 x x x x 1 8x x x 9 x 1 x x x2 1 x x x x 6 x x x 6 x 7 x 3 x x 1 x x 9 x 2 x x x 47 x x 8 x x 5 x x x(x*x-6x-9)-x(x*x-8x-15)+2x(3-x) 求一个数独答案X X X 9 X X X 8 2 X 6 3 X X 1 4 X 99 X 8 X X X X X XX X X 6 7 X 3 X XX 4 6 X 5 X 2 9 XX X 7 X 2 3 X X XX X X X X X 7 X 17 X 4 3 X X 6 2 X6 3 X X X 7 X X X 七年级下册政治复习提纲(山东人民出版社)第五单元是青春的脚步青春的气息别弄错了啊!格式：X X X X X X X X X 1、X X X X X X X X X X.2、X X X X X X X X X.3、X X X X X X X X X X X. x(x-2)(x-3) {x|(x+3)(x-2) -x^3+x^2-x 难倒爱因斯坦的九宫格X 7 X | X 8 1 | X X X |X X X | X 4 X | 7 5 9 |X X 5 | 7 X 9 | X 1 4 |5 X X | X X 8 | 3 9 X |3 9 6 | 4 X 7 | X X 2 |X 8 7 | 9 X X | X X X |4 X X | 6 X 5 | X X X | X X 4 | X X 1 |2 X X | X X X | X X X | X 3 X | X X X |X 6 x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少? x×x+3x-9/ x+2 x+2x+3x+.+100x (x*x-3)*(x*x-3)-x*(x*x-3)-2x*x 因式分解如下9*9宫图如何填x x x 1 x x x 2 9x x 5 x x x x x 4x 6 8 x x x x x xx x x 7 x x 5 x xx 2 x x 6 x x 8 xx x 3 x x 9 x x xx x x x 5 x 1 6 x 4 x x x 3 x x x x 7 x x x x 2 x x x 解九宫格题目（X为未知数）9 X 2 X 7 X 8 X XX X 4 X X 9 X 6 X1 3 X 5 X X X X 24 X X 8 5 X X 1 XX 8 9 4 X 1 6 7 XX 1 X X 3 6 X X 88 X X X X 2 X 3 6X 5 X 6 X X 9 X XX X 7 X 4 X 2 X 1 2x+3x+4x+5x+x+6x+7x=100 x+2/x+1-x+4/x+3=x+6/x+5-x+8/x+7 x=? 计算:[(x+2)/(x+3) - (x+1)/(x+2) + (x+4)/(x+5) - (x+3)/(x+4) / (x^2 + 7x + 13)/(x^2 + 8x + 15)