早教吧 育儿知识 作业答案 考试题库 百科 知识分享

1.(1/2x-2y)^22.(2xy+1/5x)^23.(n+1)^2-n^24.(2x+5y)^25.(1/3m-1/2)^26.(-2t-1)^2如:(2x-3)^2=(2x)^2-2*(2x)*3+3^2=4x^2-12x+9

题目详情
1.(1/2x-2y)^2
2.(2xy+1/5x)^2
3.(n+1)^2-n^2
4.(2x+5y)^2
5.(1/3m-1/2)^2
6.(-2t-1)^2
如:
(2x-3)^2
=(2x)^2-2*(2x)*3+3^2
=4x^2-12x+9
▼优质解答
答案和解析
(1)原式=(1/2x)^2=2*1/2x*2y+(2y)^2=1/4x^2-2xy+4y^2
(2)原式=(2xy)^2+2*(2xy)*(1/5x)+(1/5x)^2=4x^2y^2+4/5x^2y+1/25x^2
(3)原式=n^2+2n+1-n^2=2n+1
(4)原式=(2x)^2+2*(2x)*(5y)+(5y)^2=4x^2+20xy+25y^2
(5)原式=(1/3m)^2-2*(1/3m)*(1/2)+(1/2)^2=1/9m^2-1/3m+1/4
(6)原式=(-2t)^2-2*(-2t)*(1)+1=4t^2+4t+1