作业帮高分求几道初二计算题,
来源：学生作业帮 编辑：作业帮 分类：数学作业 时间：2024/05/11 12:25:42
高分求几道初二计算题,
(2x+y)^2-(x+2y)^2
49(a-b)^2-16(a+b)^2
(a-B)x^2+(b-a)Y^2
(2x+y)^2-(x+2y)^2
49(a-b)^2-16(a+b)^2
(a-B)x^2+(b-a)Y^2
1.(2x+y)^2-(x+2y)^2 =(2x+y+x+2y)*[2x+y-(x+2y)]=(3x+3y)*(x-y) = 3x^2 - 3y^2
2.49(a-b)^2-16(a+b)^2 =[7(a-b)]^2 - [4(a+b)]^2 = [7a-7b + 4a+4b] * [7a-7b -(4a+4b)] =(11a-3b)*(3a-11b)= 33a^2 + 33b^2 -130ab
3.(a-b)x^2+(b-a)Y^2 = (a-b)x^2 - (a-b)Y^2 = (a-b)(x^2 - Y^2) 还可以进一步等于（a-b）(x-y)(x+y)
2.49(a-b)^2-16(a+b)^2 =[7(a-b)]^2 - [4(a+b)]^2 = [7a-7b + 4a+4b] * [7a-7b -(4a+4b)] =(11a-3b)*(3a-11b)= 33a^2 + 33b^2 -130ab
3.(a-b)x^2+(b-a)Y^2 = (a-b)x^2 - (a-b)Y^2 = (a-b)(x^2 - Y^2) 还可以进一步等于（a-b）(x-y)(x+y)