14知识技能①.(2x+y+1)(2x+y-1)=?②.(x-2)(x+2)-(x+1)(x-3)=?③(ab+1)的平方-(ab-)的平方=?④.(2x-y)的平方-4(x-y)(x+2y)=?⑤.63的平方=?⑥.998的平方=?⑦.(a+b)的立方=?快点啊、今天晚
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/28 19:48:42
![14知识技能①.(2x+y+1)(2x+y-1)=?②.(x-2)(x+2)-(x+1)(x-3)=?③(ab+1)的平方-(ab-)的平方=?④.(2x-y)的平方-4(x-y)(x+2y)=?⑤.63的平方=?⑥.998的平方=?⑦.(a+b)的立方=?快点啊、今天晚](/uploads/image/z/2428216-16-6.jpg?t=14%E7%9F%A5%E8%AF%86%E6%8A%80%E8%83%BD%E2%91%A0.%EF%BC%882x%2By%2B1%EF%BC%89%282x%2By-1%29%3D%3F%E2%91%A1.%EF%BC%88x-2%EF%BC%89%EF%BC%88x%2B2%EF%BC%89-%EF%BC%88x%2B1%EF%BC%89%EF%BC%88x-3%EF%BC%89%3D%3F%E2%91%A2%EF%BC%88ab%2B1%EF%BC%89%E7%9A%84%E5%B9%B3%E6%96%B9-%EF%BC%88ab-%EF%BC%89%E7%9A%84%E5%B9%B3%E6%96%B9%3D%3F%E2%91%A3.%EF%BC%882x-y%EF%BC%89%E7%9A%84%E5%B9%B3%E6%96%B9-4%EF%BC%88x-y%EF%BC%89%EF%BC%88x%2B2y%EF%BC%89%3D%3F%E2%91%A4.63%E7%9A%84%E5%B9%B3%E6%96%B9%3D%3F%E2%91%A5.998%E7%9A%84%E5%B9%B3%E6%96%B9%3D%3F%E2%91%A6.%28a%2Bb%29%E7%9A%84%E7%AB%8B%E6%96%B9%3D%3F%E5%BF%AB%E7%82%B9%E5%95%8A%E3%80%81%E4%BB%8A%E5%A4%A9%E6%99%9A)
14知识技能①.(2x+y+1)(2x+y-1)=?②.(x-2)(x+2)-(x+1)(x-3)=?③(ab+1)的平方-(ab-)的平方=?④.(2x-y)的平方-4(x-y)(x+2y)=?⑤.63的平方=?⑥.998的平方=?⑦.(a+b)的立方=?快点啊、今天晚
14知识技能
①.(2x+y+1)(2x+y-1)=?②.(x-2)(x+2)-(x+1)(x-3)=?
③(ab+1)的平方-(ab-)的平方=?
④.(2x-y)的平方-4(x-y)(x+2y)=?
⑤.63的平方=?
⑥.998的平方=?
⑦.(a+b)的立方=?
快点啊、今天晚上就得写完、明天就交仂、
14知识技能①.(2x+y+1)(2x+y-1)=?②.(x-2)(x+2)-(x+1)(x-3)=?③(ab+1)的平方-(ab-)的平方=?④.(2x-y)的平方-4(x-y)(x+2y)=?⑤.63的平方=?⑥.998的平方=?⑦.(a+b)的立方=?快点啊、今天晚
考得你的是a²-b²=(a+b)(a-b),(a+b)²=a²+2ab+b²
①.(2x+y+1)(2x+y-1)=(2x+y)²-1²=4x²+4xy+y²-1
②.(x-2)(x+2)-(x+1)(x-3)=x²-4-x²+2x+3=2x-1
③(ab+1)的平方-(ab-)的平方=?减一吧
(ab+1)²-(ab-1)²=(ab+1+ab-1)(ab+1-ab+1)=2ab*2=4ab
④.(2x-y)²-4(x-y)(x+2y)= 4x²-4xy+y²-4x²-4xy+8y²=9y²-8xy
⑤.63的平方=(60+3)²=3600+9+2*3*60=3600+360+9=3969
⑥.998的平方=(100-2)²=10000+4-400=9604
⑦.(a+b)的立方=(a+b)^3
=(a+b)^2*(a+b)
=(a^2+2ab+b^2)(a+b)
=a^3+a^2b+2a^2b+2ab^2+ab^2+b^3
=a^3+b^3+3a^b+3ab^2 =a³+3ab²+3a²b+b³