1.(x+1/4)的平方-(x-1/4)(x-1/4)=1/42.(x+1)(x-1)-(x+20)的平方=7

来源:学生作业帮助网 编辑:六六作业网 时间:2024/11/28 14:56:42
1.(x+1/4)的平方-(x-1/4)(x-1/4)=1/42.(x+1)(x-1)-(x+20)的平方=71.(x+1/4)的平方-(x-1/4)(x-1/4)=1/42.(x+1)(x-1)-(

1.(x+1/4)的平方-(x-1/4)(x-1/4)=1/42.(x+1)(x-1)-(x+20)的平方=7
1.(x+1/4)的平方-(x-1/4)(x-1/4)=1/4
2.(x+1)(x-1)-(x+20)的平方=7

1.(x+1/4)的平方-(x-1/4)(x-1/4)=1/42.(x+1)(x-1)-(x+20)的平方=7
1.(x+1/4)的平方-(x-1/4)(x-1/4)=1/4
说明 [(x+1/4)+(x-1/4)]*[(x+1/4)-(x-1/4)]=1/4
即 2x*1/2=1/4 所以2x=1/2 x=1/4
2.(x+1)(x-1)-(x+20)的平方=7
说明 x^2-1-(x^2+40x+400)=7
即 -40x=408 得x=10.2

hgg