初一数学题~！完全平方问题·@·!10悬赏

来源：百度知道 编辑：UC知道 时间：2024/06/11 03:27:55
1.(2x+5y)^2
2.(1/3m-1/2)^2
3.(-2t-1)^2

过程

1. =4x^2+2x*5y*2+25y^2
=4x^2+20xy+25y^2

2. =1/9m^2-(1/3m)*1/2*2+1/4
=1/9m^2-1/3m+1/4

3. =4t^2+2t*1*2+1
=4t^2+4+1

1.(2x+5y)^2
=(2x)^2+2*2x*5y+(5y)^2
=4x^2+20xy+25y^2
2.(1/3m-1/2)^2
=(1/3m)^2-2*1/3m*1/2+(1/2)^2
=1/9m^2-1/3m+1/4
3.(-2t-1)^2
=-[(2t)^2+2*2t*2+1^2]
=-(4t^2+4t+1)
=-4t^2-4t-1

1(2x+5y)^2
=4x^2+20xy+25y^2
2(1/3m-1/2)^2
=1/9m^2-1/3m+1/4
3(-2t-1)^2
=4t^2+4t+1